2nd hardware UART

**tumbleweed** · - 12th August 2024, 14:30

You might want to post what you've tried so we can give you some 'tips'

**rocket_troy** · - 12th August 2024, 16:21

Originally Posted by tumbleweed

You might want to post what you've tried so we can give you some 'tips'

Code:

OSCFRQ = %1000 '64Mhz

Define OSC 64

' Set receive register to receiver enabled
' Set transmit register to transmitter enabled
DEFINE HSER_RXREG PORTC
DEFINE HSER_RXBIT 4
DEFINE HSER_TXREG PORTC
DEFINE HSER_TXBIT 5
DEFINE HSER_BAUD 9600

' Set receive register to receiver enabled
' Set transmit register to transmitter enabled
'DEFINE HSER2_RXREG PORTB
'DEFINE HSER2_RXBIT 3
'DEFINE HSER2_TXREG PORTB
'DEFINE HSER2_TXBIT 0
'DEFINE HSER2_BAUD 9600

'This works
hSerout ["Test",13,10]

'This doesn't
hSerout2 ["Test",13,10]

**rocket_troy** · - 13th August 2024, 00:44

Apologies, here is the actual code:

Code:

OSCFRQ = %1000 '64Mhz

Define OSC 64

PRECISION  CON 8 SYSTEM  '8 byte = 64 bit precision
INCLUDE "N-Bit_Math.pbp"

DEFINE HSER2_RXREG PORTB
DEFINE HSER2_RXBIT 3
DEFINE HSER2_TXREG PORTB
DEFINE HSER2_TXBIT 0
DEFINE HSER2_BAUD 9600

DEFINE HSER_RXREG PORTC
DEFINE HSER_RXBIT 4
DEFINE HSER_TXREG PORTC
DEFINE HSER_TXBIT 5
DEFINE HSER_BAUD 9600
 
ANSELA = %00000000 'Everything Digital
ANSELB = %00000000 'Everything Else Digital
ANSELC = %00000000 'Everything Else Digital

TRISB.0 = 0 
TRISB.3 = 1 
TRISC.4 = 1 
TRISC.5 = 0 

'works
hSerout ["Test",13,10]

'doesn't work
hSerout2 ["Test",13,10]

**robertg** · - 13th August 2024, 10:33

I'm far from an expert in this space. And haven't used the second USART port on a PIC
But maybe PMD5 register for UART2 isn't being set correctly by picbasic??

bit 5 U2MD: Disable UART2 bit
1 = UART2 module disabled
0 = UART2 module enabled
bit 4 U1MD: Disable UART1 bit
1 = UART1 module disabled
0 = UART1 module enabled

**richard** · - 13th August 2024, 11:30

I'm far from an expert in this space. And haven't used the second USART port on a PIC
But maybe PMD5 register for UART2 isn't being set correctly by picbasic??

extremely unlikely

note power on defaults for PDM5
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did you try setting uart regs like mcc suggests ?
note uart registers

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**rocket_troy** · - 13th August 2024, 16:43

Regarding setting the regs directly: this is what I've tried (note this is set to 115200 baud as that was the original objective)

Code:

OSCFRQ = %1000 '64Mhz

Define OSC 64

PRECISION  CON 8 SYSTEM  '8 byte = 64 bit precision
INCLUDE "N-Bit_Math.pbp"

'Use for hardware serial comms to SD card module
'******************************************************************************
'Configure UART Control Register 0
U2CON0.7 = 1 'BRGS = 1 (high speed baud generator)
U2CON0.6 = 0 'ABDEN = 0 Auto-baud Detect Disabled 
U2CON0.5 = 1 'TXEN: Transmit Enabled
U2CON0.4 = 1 'RXEN: Receive Disabled
U2CON0.3 = 0 '0000 = Asynchronous 8-bit UART mode
U2CON0.2 = 0 '0000 = Asynchronous 8-bit UART mode
U2CON0.1 = 0 '0000 = Asynchronous 8-bit UART mode
U2CON0.0 = 0 '0000 = Asynchronous 8-bit UART mode

U2CON1.7 = 0 'Turn Serial port 2 off for baud setting
 
U2BRGL = 138  'Baud Divisor low byte
U2BRGH = 0    'Baud Divisor high byte

U2RXPPS = %1011 'Assign UART RX pin to RB3
RB0PPS = %010110  'Assign UART2 TX pin to RB0
 
U2CON1.7 = 1 'Turn Serial port 2 on
'******************************************************************************
 
'Configure AN2 as Analog Inputs (PortA2)
ANSELB = %00000000 'Everything Digital

TRISB.0 = 0 'SD_Card_TX Hardware UART
TRISB.3 = 1 'SD_Card_RX Hardware UART

hSerout2 ["Test",13,10]

That doesn't provide any joy either.

**HenrikOlsson** · - 13th August 2024, 20:36

I was going to say that you need to unlock the PPS before trying to configuring it but reading the datasheet it looks like it is unlocked at POR - I've always thought it was the other way around.

Anyway, here's the relevant parts from a project of mine which uses both UARTS, in this particular case I even use the PPS peripheral to switch UART2 pins around to two different devices. Using HSEROUT / HSEROUT2 in the code it worked out fine. This is for a 67K40 so it won't match your setup but perhaps it can provide some pointers.

Code:

'----------------------------------------------------
' PPS Unlock
PPSLOCK = $55
PPSLOCK = $AA
@ BCF PPSLOCK, PPSLOCKED

RC6PPS = $0C                                ' We want PORTC.6 as EUSART1 TX
RX1PPS = %00010111                          ' We want PORTC.7 as EUSART1 RX

RG7PPS = $0E                                ' We want EUSART2 TX on PortG.7 
RX2PPS = %00110010                          ' We want EUSART2 RX on PortG.2 

' Since we're switching UART pins around during runtime we need to leave the PPS lock open.
'PPSLOCK = $55
'PPSLOCK = $AA
'@ BSF PPSLOCK, PPSLOCKED
'----------------------------------------------------

ANSELA = %00110000                          ' RA4, 5 analog, rest digital 
ANSELB = 0
ANSELD = 0
ANSELE = 0
ANSELF = 0
ANSELG = 0


' Setup for EUSART1 
RCSTA1 = $90                                ' Enable serial port & continuous receive
TXSTA1 = $24                                ' Enable transmit, BRGH = 1
SPBRG1 = 64                                 ' 19200 Baud @ 64MHz, 0,04%
SPBRGH1 = 3
BAUDCON1.3 = 1                              ' Enable 16 bit baudrate generator


' Setup for EUSART2 
RCSTA2 = $90                                ' Enable serial port & continuous receive
TXSTA2 = $24                                ' Enable transmit, BRGH = 1
SPBRG2 = 138                                ' 115200 Baud @ 64MHz, -0,08%
SPBRGH2 = 0
BAUDCON2.3 = 1                              ' Enable 16 bit baudrate generator


TRISC.6 = 0                                 ' UART1 TX
TRISC.7 = 1                                 ' UART1 RX

TRISG.7 = 0                                 ' UART2 TX 
TRISG.2 = 1                                 ' UART2 RX

/Henrik.

**richard** · - 13th August 2024, 00:52

you don't appear to have set the portb pins used to digital [anselb =$f6]

or not

mcc sets the involved registers like this to match your settings

TRISB = 0xFE;
ANSELB = 0xF6;
U2RXPPS = 0x0B; //RB3->UART2:RX2;
RB0PPS = 0x16; //RB0->UART2:TX2;
U2P1L = 0x00;
U2P1H = 0x00;
U2P2L = 0x00;
U2P2H = 0x00;
U2P3L = 0x00;
U2P3H = 0x00;
U2CON0 = 0xB0;
U2CON1 = 0x80;
U2CON2 = 0x00;
U2BRGL = 0x82;
U2BRGH = 0x06;
U2FIFO = 0x00;
U2UIR = 0x00;
U2ERRIR = 0x00;
U2ERRIE = 0x00;

**rocket_troy** · - 13th August 2024, 02:37

I'm guessing this is a reply to my 1st code post which I inadvertently cut the TRIS settings in my (hastily) attempt for reader friendly pruning, but I can assure you every port was set to digital all the time. What's more, the 2nd UART was originally configured to the same pins as the 1st. When my head was too sore from banging against that wall, I switched the 1st UART to those pins and voila, they worked.

Troy

Originally Posted by richard

you don't appear to have set the portb pins used to digital [anselb =$f6]

or not

mcc sets the involved registers like this to match your settings

TRISB = 0xFE;
ANSELB = 0xF6;
U2RXPPS = 0x0B; //RB3->UART2:RX2;
RB0PPS = 0x16; //RB0->UART2:TX2;
U2P1L = 0x00;
U2P1H = 0x00;
U2P2L = 0x00;
U2P2H = 0x00;
U2P3L = 0x00;
U2P3H = 0x00;
U2CON0 = 0xB0;
U2CON1 = 0x80;
U2CON2 = 0x00;
U2BRGL = 0x82;
U2BRGH = 0x06;
U2FIFO = 0x00;
U2UIR = 0x00;
U2ERRIR = 0x00;
U2ERRIE = 0x00;

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