Porting code to new PIC

[malc-c]

Guy's,

Currently have a project running on an 18F4580. It uses a DS1307 RTC which uses the I2C bus, however I'm looking at adding networking to my project based on an Enc26j60 which uses the SPI interface. I've been browsing Microchips site for best part of the morning and have located what seems to be the ideal chip to port the project to. Its an 18F45K22 (http://www.microchip.com/wwwproducts...cName=en546239)

Basically this has two MSSP however my limited knowledge of deciphering datasheets I can't work out if you can configure one MSSP as IC2 and the other as SPI and have them running at the same time ? Could someone take a look at the datasheet and advise me on my choice of chip and if I can indeed have an Ic2 and SPI bus running at the same time http://ww1.microchip.com/downloads/e...Doc/41412D.pdf

THIA

[HenrikOlsson]

Hi Malcolm,
As far as I can see they are two, of each other, completely independent peripherals, see note 1 and 2 on page 208. You should have no problem setting one up for I²C and the other for SPI. Lots of registers to set up though ;-)

Make sure to read thru the errata sheet as well, I don't see the MSSP modules being mentioned but apparently there can be some pretty serious silicon bugs. The HLVD module for example appears to be completely useless.

/Henrik.

[malc-c]

Thanks for that.

I had noted it stated independent MSSP, but I wasn't sure if it basically meant that that the chip was in SPI mode or IC2 mode. Those registers are going to be my downfall. The data sheet appears to have nearly 50 pages covering the MSSP's - any suggestions as to what PBP commands I need to achieve this mix ?

[HenrikOlsson]

Hi Malcolm,
Sorry but AFIK PBP doesn't have commands that "drives" the MSSP modules (like HSEROUT/HSERIN does with USART). I think you have to manually set up the module(s) and then, in one way or another (polling, interruptdriven etc) read and write data to them. Unfortunately I've never played with such a module - heck, I haven't even used I2CREAD/WRITE....

/Henrik.

[mackrackit]

http://melabs.com/resources/samples/pbp/spimast.htm

http://melabs.com/resources/samples/pbp/i2c.htm

[malc-c]

Thanks Dave.

My christmas present to myself arrived today - three add-on boards for the EasyPIC5 board, one of which was the Ethernet Board - I'm going to check the data sheets for the PICs I have in my hobby box and find one with an SPI interface and have some fun !

[malc-c]

http://melabs.com/resources/samples/pbp/spimast.htm

Dave, why is it that when I download the sample code for the above, I get a "symbol not previously defined SSPCON" The only difference I've made is to remove the LCD lines in the example and added the line to inc a hw file which was an edited version of the same file I used for my thermostat project

ASM 
  __CONFIG    _CONFIG1H, _OSC_HSPLL_1H
  __CONFIG    _CONFIG2L, _PWRT_ON_2L  
  __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
  __CONFIG    _CONFIG3H, _PBADEN_OFF_3H
  __CONFIG    _CONFIG4L, _LVP_OFF_4L & _XINST_OFF_4L
ENDASM


DEFINE OSC 48 

ADCON1 = $0F
clear

DEFINE LCD_DREG  PORTB           ' LCD Data port
DEFINE LCD_DBIT  0               ' starting Data bit (0 or 4)
DEFINE LCD_EREG  PORTB           ' LCD Enable port
DEFINE LCD_EBIT  5               '     Enable bit  (on EasyPIC 5 LCD)
DEFINE LCD_RSREG PORTB           ' LCD Register Select port
DEFINE LCD_RSBIT 4               '     Register Select bit   (on EasyPIC 5 LCD)
DEFINE LCD_BITS  4               ' LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 4               ' number of lines on LCD
DEFINE LCD_COMMANDUS 2000        ' Command delay time in us 
DEFINE LCD_DATAUS 50             ' Data delay time in us

The example code below

' Name        : SPIMAST.pbp
' Compiler    : PICBASIC PRO Compiler 2.6
' Assembler   : PM or MPASM
' Target PIC  : 40-pin 16F or 18F
' Hardware    : Lab-X1, Lab-X2 or similar
' Oscillator  : 4MHz internal or external
' Keywords    : LCDOUT, HARDWARE SPI MASTER
' Description : PicBasic Pro program to read and write to SPI slave
' using the hardware synchronous serial port. Connect SDI(master) to
' SDO(slave), SDO(master) to SDI(slave), AND SCK(master) to SCK(slave).
' Common ground is required.
'
' Sends ascii "?" to request data, waits for a "!" to begin receiving data.
' Expects to find the ADC conversion value in the 6th position of the received
' string.
'
INCLUDE "hw.pbp"

SSPEN VAR SSPCON.5   ' SSP Enable bit
CKP   VAR SSPCON.4   ' Clock Polarity Select
SMP   VAR SSPSTAT.7  ' Data input sample phase
CKE   VAR SSPSTAT.6  ' Clock Edge Select bit
SSPIF VAR PIR1.3     ' SPI interrupt flag

i VAR BYTE           ' loop counter
a VAR BYTE[6]        ' Holds 6 characters read from slave

   ADCON1 = 7        ' Set PORTA and PORTE to digital
   Low PORTE.2       ' LCD R/W line low (W)
   Pause 100         ' Wait for LCD to start up

   TRISC = 0         ' set PORTC I/O
   SSPEN = 1         ' enable SPI pins
   CKP = 0           ' clock idle low
   CKE = 0           ' transmit on idle to active transition
   SSPIF = 0         ' clear buffer full status
   SMP = 0           ' sample in middle of data
                
mainloop:
   GoSub getdata     ' initiate conversion and receive data
   LCDOut $fe, 1, STR a\5, DEC a[5] ' display received string
   Pause 100
   GoTo mainloop     ' do it forever

getdata:                                        
   SSPBUF = "?"      ' send ? to start conversion
   GoSub letclear    ' wait for buffer to clear
   IF SSPBUF<>"!" Then getdata ' wait for reply (!)

   For i = 0 to 5    ' loop for 6 characters
     SSPBUF = 0      ' write to SSPBUF to start clock
     GoSub letclear  ' wait for receipt
     a[i] = SSPBUF   ' store received character in array
   Next i            ' get next character
   Return

letclear:
   IF SSPIF = 0 Then letclear ' wait for SPI interupt flag
   PauseUs 25         ' 25uS fudge factor
   SSPIF = 0          ' reset flag
   Return

   End

PIC is the same 18F4580 used for my Thermostat project - Help !!