MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

**gadelhas** · - 1st February 2012, 18:42

Hi everyone;

In a project that came up was necessary to use the MCP23S17. After searching the forum, i did not find any example that would satisfy my needs.

For this reason, I decided to write my own code to communicate with the MCP23S17. There were written three different approaches to communicate with the IC.

The first uses only PBP and the commands and shiftin ShiftOut, the second approach, uses the MSSP module of the PIC IC with PBP, and the third, also uses the MSSP module, but the "send" and "receive" routines were written in ASM.

The following three examples below, one per post. In each post you can see the size of the code, and the time that takes to execute the "Send" and "receive" routine.

All codes are commented well enough to understand its operation. Also the schematic is founded attached, and the Proteus simulation. ( You must take off the ".txt" from each file )

The code was written in Microcode Studio 3.0.0.5 and PBP2.60C.
The IC that was used is PIC16F887.
To test the codes, was used the development board Mikroelektronika EASYPICv6 and software PROTEUS 7.7 SP2.

I hope it will be useful to someone.

**gadelhas** · - 1st February 2012, 18:46

Code:

'****************************************************************
'*  Name    : MCP23S17 + PBP + ShiftIN & ShiftOut               *
'*  Author  : [GADELHAS]                                        *
'*  Notice  : Copyright (c) 2012                                *
'*          : All Rights Reserved                               *
'*  Date    : 31-01-2012                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          : EASYPICV6 + PIC16F887 + MCP23S17                  *
'****************************************************************
'                              CONFIGS
' ================================================================
@ __CONFIG _CONFIG1, _HS_OSC & _WDT_OFF & _PWRTE_OFF & _MCLRE_ON & _CP_OFF & _BOR_OFF & _DEBUG_OFF & _LVP_OFF & _FCMEN_ON & _IESO_OFF  
@ __CONFIG _CONFIG2, _WRT_OFF & _BOR40V'                          DEFINES & INCLUDES
' ================================================================
 DEFINE OSC 8
 include "modedefs.bas"
'                REGISTERS AND PINOUT ( 1 = IN; 0 = OUT )
' ================================================================
           '76543210          '76543210
 TRISA   = %00000000: PORTA = %00000000 
 TRISB   = %00000000: PORTB = %00000000
 TRISC   = %00000000: PORTC = %00000000
 TRISD   = %00000000: PORTD = %00000000
 TRISE   = %00000000: PORTE = %00000000
 ADCON0  = %00000000
 ADCON1  = %00000000
 ANSEL   = %00000000 
 ANSELH  = %00000000
 CM1CON0 = %00000000
 CM2CON0 = %00000000
 
'                         ALIAS & MODIFIERS
' ================================================================
  nCS VAR PORTA.2 
 nRST VAR PORTA.3
 SCLK VAR PORTC.3
  SDI VAR PORTC.4
  SDO VAR PORTC.5
  
'                        VARIABLES & COSTANTS
' ================================================================
 MCPWRT CON $40    'Command o write in MCP23S17 Address $00
 MCPRED CON $41    'Command o read from MCP23S17 Address $00
 IOCON  CON $0A    'Register address to MCP23S17 Config
 IODIRA CON $00    'Register address to MCP23S17 PortA(1)
 IODIRB CON $01    'Register address to MCP23S17 PortB(2)
 GPIOA  CON $12    'Register address to MCP23S17 GPIOA(1)
 GPIOB  CON $13    'Register address to MCP23S17 GPIOB(2)
 OLATA  CON $14    'Register address to MCP23S17 LATA(1)
 OLATB  CON $15    'Register address to MCP23S17 LATB(2)
  
 DataOut VAR BYTE  'Variable for Data Byte to Send to the MCP23S17
 DataIn  VAR BYTE  'Variable for Data Byte to Receive from the MCP23S17
 MCPReg  VAR BYTE  'Variable for the Register to Send to the MCP23S17
 
'                           PROGRAM INIT
' ================================================================
    GOSUB INIT_MCP23S17    'Init the MCP23S17
'                            MAIN LOOP
' ================================================================
MAIN:
    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17
    
    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC
    
    PAUSE 200
GOTO MAIN
'                              SUB - ROTINES
' ================================================================    
INIT_MCP23S17:
    nRST = 0                'Reset the port expander
    PAUSE 1
    nRST = 1
    MCPReg = IOCON          'Configures the MCP23S17
    DataOut = $20
    GOSUB SEND_MCP23S17
    MCPReg = IODIRA         'Configures PortA(1) All Output
    DataOut = $00
    GOSUB SEND_MCP23S17
    
    MCPReg = IODIRB         'Configures PortB(2) All Input
    DataOut = $FF
    GOSUB SEND_MCP23S17      
RETURN
SEND_MCP23S17:
    nCS = 0                'Enable the MCP23S17
    SHIFTOUT SDO, SCLK, MSBFIRST, [MCPWRT,MCPReg,DataOut]        
    nCS = 1                'Disable the MCP23S17
RETURN
RECEIVE_MCP23S17:
    nCS = 0                'Enable the MCP23S17
    SHIFTOUT SDO, SCLK, MSBFIRST, [MCPRED,MCPReg]        
    SHIFTIN SDI, SCLK, MSBPRE, [DataIn]    
    nCS = 1                'Disable the MCP23S17
RETURN
END

Size: 285 Words

Time to execute the following Routine ( Send) - 990 ticks -> 495.0uS

Code:

    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17

Time to execute the following Routine ( Receive) - 927 ticks -> 463.1uS

Code:

    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC

**gadelhas** · - 1st February 2012, 18:50

Code:

'****************************************************************
'*  Name    : MCP23S17 + MSPP + PBP                             *
'*  Author  : [GADELHAS]                                        *
'*  Notice  : Copyright (c) 2012                                *
'*          : All Rights Reserved                               *
'*  Date    : 31-01-2012                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          : EASYPICV6 + PIC16F887 + MCP23S17                  *
'****************************************************************
'                              CONFIGS
' ================================================================
@ __CONFIG _CONFIG1, _HS_OSC & _WDT_OFF & _PWRTE_OFF & _MCLRE_ON & _CP_OFF & _BOR_OFF & _DEBUG_OFF & _LVP_OFF & _FCMEN_ON & _IESO_OFF  
@ __CONFIG _CONFIG2, _WRT_OFF & _BOR40V'                          DEFINES & INCLUDES
' ================================================================
 DEFINE OSC 8
'                REGISTERS AND PINOUT ( 1 = IN; 0 = OUT )
' ================================================================
           '76543210          '76543210
 TRISA   = %00000000: PORTA = %00000000 
 TRISB   = %00000000: PORTB = %00000000
 TRISC   = %00010000: PORTC = %00000000
 TRISD   = %00000000: PORTD = %00000000
 TRISE   = %00000000: PORTE = %00000000
 ADCON0  = %00000000
 ADCON1  = %00000000
 ANSEL   = %00000000 
 ANSELH  = %00000000
 CM1CON0 = %00000000
 CM2CON0 = %00000000
 SSPSTAT = %00000000  'Configures the SPI Module ( Read DataSheet ) 
 SSPCON  = %00110000  'Configures the SPI Module ( Read DataSheet ) 
 
'                         ALIAS & MODIFIERS
' ================================================================
  nCS VAR PORTA.2 
 nRST VAR PORTA.3
 SCLK VAR PORTC.3
  SDI VAR PORTC.4
  SDO VAR PORTC.5
  
'                        VARIABLES & COSTANTS
' ================================================================
 MCPWRT CON $40    'Command o write in MCP23S17 Address $00
 MCPRED CON $41    'Command o read from MCP23S17 Address $00
 IOCON  CON $0A    'Register address to MCP23S17 Config
 IODIRA CON $00    'Register address to MCP23S17 PortA(1)
 IODIRB CON $01    'Register address to MCP23S17 PortB(2)
 GPIOA  CON $12    'Register address to MCP23S17 GPIOA(1)
 GPIOB  CON $13    'Register address to MCP23S17 GPIOB(2)
 OLATA  CON $14    'Register address to MCP23S17 LATA(1)
 OLATB  CON $15    'Register address to MCP23S17 LATB(2)
  
 DataOut VAR BYTE  'Variable for Data Byte to Send to the MCP23S17
 DataIn  VAR BYTE  'Variable for Data Byte to Receive from the MCP23S17
 MCPReg  VAR BYTE  'Variable for the Register to Send to the MCP23S17
 
'                           PROGRAM INIT
' ================================================================
    GOSUB INIT_MCP23S17    'Init the MCP23S17
'                            MAIN LOOP
' ================================================================
MAIN:
    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17
    
    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC
    
    PAUSE 200
GOTO MAIN
'                              SUB - ROTINES
' ================================================================    
INIT_MCP23S17:
    nRST = 0                'Reset the port expander
    PAUSE 1
    nRST = 1
    MCPReg = IOCON          'Configures the MCP23S17
    DataOut = $20
    GOSUB SEND_MCP23S17
    MCPReg = IODIRA         'Configures PortA(1) All Output
    DataOut = $00
    GOSUB SEND_MCP23S17
    
    MCPReg = IODIRB         'Configures PortB(2) All Input
    DataOut = $FF
    GOSUB SEND_MCP23S17      
RETURN
SEND_MCP23S17:
    nCS = 0                 'Enable the MCP23S17
    SSPBUF = MCPWRT         'Command to Write to the MCP23S17
    PAUSEUS 1    
    SSPBUF = MCPReg         'Register to Write the Data
    PAUSEUS 1 
    SSPBUF = DataOut        'Data to be sent
    PAUSEUS 1           
    nCS = 1                 'Disable the MCP23S17
RETURN
RECEIVE_MCP23S17:
    nCS = 0                 'Enable the MCP23S17
    SSPBUF = MCPRED         'Command to Read from the MCP23S17
    PAUSEUS 1 
    SSPBUF = MCPReg         'Register to Read from
    PAUSEUS 1  
    SSPBUF = 0              'Send something
    PAUSEUS 1  
    DataIn = SSPBUF         'Data received from te MCP23S17
    PAUSEUS 1 
    nCS = 1                 'Disable the MCP23S17
RETURN
END

Size: 166 Words

Time to execute the following Routine ( Send) - 92 ticks -> 46.0uS

Code:

    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17

Time to execute the following Routine ( Receive) - 119 ticks -> 59.1uS

Code:

    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC

**gadelhas** · - 1st February 2012, 18:53

Code:

'****************************************************************
'*  Name    : MCP23S17 + MSPP + ASM                             *
'*  Author  : [GADELHAS]                                        *
'*  Notice  : Copyright (c) 2012                                *
'*          : All Rights Reserved                               *
'*  Date    : 31-01-2012                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          : EASYPICV6 + PIC16F887 + MCP23S17                  *
'****************************************************************
'                              CONFIGS
' ================================================================
@ __CONFIG _CONFIG1, _HS_OSC & _WDT_OFF & _PWRTE_OFF & _MCLRE_ON & _CP_OFF & _BOR_OFF & _DEBUG_OFF & _LVP_OFF & _FCMEN_ON & _IESO_OFF  
@ __CONFIG _CONFIG2, _WRT_OFF & _BOR40V
'                          DEFINES & INCLUDES
' ================================================================
 DEFINE OSC 8
'                REGISTERS AND PINOUT ( 1 = IN; 0 = OUT )
' ================================================================
           '76543210          '76543210
 TRISA   = %00000000: PORTA = %00000100 
 TRISB   = %00000000: PORTB = %00000000
 TRISC   = %00010000: PORTC = %00000000
 TRISD   = %00000000: PORTD = %00000000
 TRISE   = %00000000: PORTE = %00000000
 ADCON0  = %00000000
 ADCON1  = %00000000
 ANSEL   = %00000000 
 ANSELH  = %00000000
 CM1CON0 = %00000000
 CM2CON0 = %00000000
 SSPSTAT = %00000000  'Configures the SPI Module ( Read DataSheet ) 
 SSPCON  = %00110000  'Configures the SPI Module ( Read DataSheet ) 
 
'                         ALIAS & MODIFIERS
' ================================================================
  nCS VAR PORTA.2 
 nRST VAR PORTA.3
 SCLK VAR PORTC.3
  SDI VAR PORTC.4
  SDO VAR PORTC.5
  
'                        VARIABLES & COSTANTS
' ================================================================
 MCPWRT CON $40    'Command o write in MCP23S17 Address $00
 MCPRED CON $41    'Command o read from MCP23S17 Address $00
 IOCON  CON $0A    'Register address to MCP23S17 Config
 IODIRA CON $00    'Register address to MCP23S17 PortA(1)
 IODIRB CON $01    'Register address to MCP23S17 PortB(2)
 GPIOA  CON $12    'Register address to MCP23S17 GPIOA(1)
 GPIOB  CON $13    'Register address to MCP23S17 GPIOB(2)
 OLATA  CON $14    'Register address to MCP23S17 LATA(1)
 OLATB  CON $15    'Register address to MCP23S17 LATB(2)
 
 DataOut VAR BYTE  'Variable for Data Byte to Send to the MCP23S17
 DataIn  VAR BYTE  'Variable for Data Byte to Receive from the MCP23S17
 MCPReg  VAR BYTE  'Variable for the Register to Send to the MCP23S17
 
'                           PROGRAM INIT
' ================================================================
    GOSUB INIT_MCP23S17    'Init the MCP23S17
'                            MAIN LOOP
' ================================================================
MAIN:
    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17
    
    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC
    
    PAUSE 200
GOTO MAIN
'                              SUB - ROTINES
' ================================================================    
INIT_MCP23S17:
    nRST = 0                'Reset the port expander
    PAUSE 1
    nRST = 1
    MCPReg = IOCON          'Configures the MCP23S17
    DataOut = $20
    GOSUB SEND_MCP23S17
    MCPReg = IODIRA         'Configures PortA(1) All Output
    DataOut = $00
    GOSUB SEND_MCP23S17
    
    MCPReg = IODIRB         'Configures PortB(2) All Input
    DataOut = $FF
    GOSUB SEND_MCP23S17      
RETURN
SEND_MCP23S17:  
ASM
 bcf PORTA, 2               ;Enable the MCP23S17
 MOVE?CB _MCPWRT, SSPBUF    ;Command to Write to the MCP23S17
 call _delay
 MOVE?BB _MCPReg, SSPBUF    ;Register to Write the Data
 call _delay
 MOVE?BB _DataOut, SSPBUF   ;Data to be sent
 call _delay                
 bsf PORTA, 2               ;Disable the MCP23S17
ENDASM
RETURN
RECEIVE_MCP23S17:
ASM
 bcf PORTA, 2               ;Enable the MCP23S17
 MOVE?CB _MCPRED, SSPBUF    ;Command to Read from the MCP23S17
 call _delay
 MOVE?BB _MCPReg, SSPBUF    ;Register to Read from
 call _delay
 MOVE?BB _DataOut, SSPBUF   ;Send something
 call _delay 
 MOVE?BB SSPBUF, _DataIn    ;Data received from te MCP23S17
 bsf PORTA, 2               ;Disable the MCP23S17
ENDASM
RETURN
delay:                      'Delay Routine 3uS - You may have to change if running OSC faster  
asm                         ;8Mhz/4 = 2Mhz = 0.5uS X 6cycles(2 p/goto) = 3uS
 goto $+1
 goto $+1
 goto $+1
endasm
return
END

Size: 157 Words

Time to execute the following Routine ( Send) - 47 ticks -> 23.1uS

Code:

    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    GOSUB SEND_MCP23S17

Time to execute the following Routine ( Receive) - 50 ticks -> 25.0uS

Code:

    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
    GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
    PORTB = DataIn           'PIC

**Demon** · - 2nd February 2012, 01:31

This is great stuff. I use the MCP23016, but this new IC is much faster.

Can you explain how you came up with the 3us delay in the 3rd approach? I look at your comment and the SPI characteristics in the datasheet and don't know what to use exactly.

Robert

**gadelhas** · - 2nd February 2012, 12:48

Originally Posted by Demon

This is great stuff. I use the MCP23016, but this new IC is much faster.

Can you explain how you came up with the 3us delay in the 3rd approach? I look at your comment and the SPI characteristics in the datasheet and don't know what to use exactly.

Robert

Hi Robert, Thanks for your comment.

Hi came up with 3 uS by trial and error. I tried 2 uS, but it wasn´t enough. The problem is not the MCP23S17, but the SSPUBUF register of the PIC. I think if you run the PIC faster, for instance @20Mhz, you can even reduce that time.

**Yvesmazzon** · - 6th February 2012, 08:31

Hi Gaelas,
I realized when you mailed the above was quite a while ago. Did you ever extendedyour code to drive a 8 or 4 bits LCD? I am using PicDem board and also the ISISversion but both are written in PASM and trying to get the PBP or Proton basicto do the same thing. Any advises or basic code will be welcome.
Regards,
Yves

**gadelhas** · - 6th February 2012, 14:11

Originally Posted by Yvesmazzon

Hi Gaelas,
I realized when you mailed the above was quite a while ago. Did you ever extendedyour code to drive a 8 or 4 bits LCD? I am using PicDem board and also the ISISversion but both are written in PASM and trying to get the PBP or Proton basicto do the same thing. Any advises or basic code will be welcome.
Regards,
Yves

Hi;

No i don't have any example how to interface the MCP with a LCD. It never was necessary. Maybe one day i develop such example, but for now i'm working on other examples.

**Ryan7777** · - 28th July 2012, 21:34

Im having trouble getting this to work. my circuit is the same as Gadelhas has in his schematic, except im not grabbing any inputs with my circuit and i'm using a different PIC . The way I have it coded is so that I can use it with a 16F648A w/ 4Mhz internal OSC and I think it should light each led on the MCP23S17s PORTA one at a time before reseting at the end of the string and repeating, but its not working in that the leds never light. I have an LED on PORTB.4 as kind of a watch dog blinky and its behaving as I would expect. Any ideas on whats wrong with my version of Gadelhas' code or something else I'm missing?

Code:

'                              CONFIGS
' ================================================================
@ DEVICE PIC16F648A, INTRC_OSC_NOCLKOUT, WDT_OFF, PWRT_OFF, MCLR_OFF, PROTECT_OFF, BOD_OFF, LVP_OFF

'                          DEFINES & INCLUDES
' ================================================================
 DEFINE OSC 4
 include "modedefs.bas"
'                REGISTERS AND PINOUT ( 1 = IN; 0 = OUT )
' ================================================================
           '76543210          
CMCON = 7                              ' Turn off un-needed PIC hardware
VRCON = 0                              '   ''             ''
CCP1CON = 0                            '   ''             ''
INTCON = %00000000                     '   ''             ''

 
'                         ALIAS & MODIFIERS
' ================================================================
  nCS VAR PORTA.0 
 nRST VAR PORTB.5
 SCLK VAR PORTB.0
  SDO VAR PORTB.3
  
'                        VARIABLES & COSTANTS
' ================================================================
 MCPWRT CON $40    'Command o write in MCP23S17 Address $00
 MCPRED CON $41    'Command o read from MCP23S17 Address $00
 IOCON  CON $0A    'Register address to MCP23S17 Config
 IODIRA CON $00    'Register address to MCP23S17 PortA(1)
 IODIRB CON $01    'Register address to MCP23S17 PortB(2)
 GPIOA  CON $12    'Register address to MCP23S17 GPIOA(1)
 GPIOB  CON $13    'Register address to MCP23S17 GPIOB(2)
 OLATA  CON $14    'Register address to MCP23S17 LATA(1)
 OLATB  CON $15    'Register address to MCP23S17 LATB(2)
  
 DataOut VAR BYTE  'Variable for Data Byte to Send to the MCP23S17
 DataIn  VAR BYTE  'Variable for Data Byte to Receive from the MCP23S17
 MCPReg  VAR BYTE  'Variable for the Register to Send to the MCP23S17
 
'                           PROGRAM INIT
' ================================================================
clear
pause 100
nrst = 1
ncs = 1
sclk = 0
sdo = 0
pause 100
    GOSUB INIT_MCP23S17    'Init the MCP23S17
'                            MAIN LOOP
' ================================================================
MAIN:
    MCPReg=OLATA             'This light up the leds, connected in
    DataOut=DataOut+1        'PortA(1) of the MCP23S17
    if dataout >=8 then
    dataout=0
    GOSUB SEND_MCP23S17
    gosub INIT_MCP23S17:
    endif
    GOSUB SEND_MCP23S17
    
'    MCPReg = GPIOB           'This read the PortB(1) of the MCP23S17
'   GOSUB RECEIVE_MCP23S17   'and show the result on the PORTB of the
'   PORTB = DataIn           'PIC
    
    PAUSE 500
    if dataout = 0 then
    high PORTB.4
    pause 250
    low PORTB.4
    pause 250
    endif 
    high PORTB.4
    pause 500
    low PORTB.4
GOTO MAIN
'                              SUB - ROTINES
' ================================================================    
INIT_MCP23S17:
    nRST = 0                'Reset the port expander
    PAUSE 1
    nRST = 1
    MCPReg = IOCON          'Configures the MCP23S17
    DataOut = $20
    GOSUB SEND_MCP23S17
    MCPReg = IODIRA         'Configures PortA(1) All Output
    DataOut = $00
    GOSUB SEND_MCP23S17
    
    MCPReg = IODIRB         'Configures PortB(2) All Input
    DataOut = $FF
    GOSUB SEND_MCP23S17      
RETURN
SEND_MCP23S17:
    nCS = 0                'Enable the MCP23S17
    SHIFTOUT SDO, SCLK, MSBFIRST, [MCPWRT,MCPReg,DataOut]        
    nCS = 1                'Disable the MCP23S17
RETURN
'RECEIVE_MCP23S17:
'    nCS = 0                'Enable the MCP23S17
'    SHIFTOUT SDO, SCLK, MSBFIRST, [MCPRED,MCPReg]        
'   SHIFTIN SDI, SCLK, MSBPRE, [DataIn]    
'    nCS = 1                'Disable the MCP23S17
'RETURN
END

**gadelhas** · - 29th July 2012, 00:49

Hi Ryan7777;

Try to add this 2 lines after the INTCON configuration and see if it works.

TRISA = %00000000
TRISB = %00000000

**gadelhas** · - 29th July 2012, 22:47

Hi Ryan7777;

Have you allready tried my sugestion?

I've tried and it worked, so you must add those to lines that i mention.
Also remember that you are working with binary numbers, so this;

Code:

    DataOut=DataOut+1        
    if dataout >=8 then

will not light up all the leds.

Thread: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Thread Tools

Search Thread

Display

Hybrid View

MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

First Approache - ShiftIn and ShiftOut ( Only PBP )

Second Approache - MSSP Module with PBP only

Third Approache - MSSP Module with PBP and ASM Send and Receive Routine

Re: Third Approache - MSSP Module with PBP and ASM Send and Receive Routine

Re: Third Approache - MSSP Module with PBP and ASM Send and Receive Routine

Re: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Re: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Re: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Re: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Re: MCP23S17 - Three different approaches - ShiftIn/ShiftOut / MSSP+PBP / MSSP+ASM

Members who have read this thread : 1

Bookmarks

Bookmarks

Posting Permissions