SPI not working on 18F26J50

[Jim Oram]

Support, using my new PCW compiler:
For several days I have been trying to get the SPI to work on a 18F26J50, (28 pin dip).
I am using:

[Ttelmah]

setup_spi, only works with the hardware SPI. No need to tell it the pins
except where you have re-mappable pins.
So:

[Jim Oram]

Support,
Thank you for the suggested code to get SPI running.
The SPI does output data now, but the reassignment of UART2 port pins to C0 and C1 does not seem to work. Is is something with the Tris setting?
I think I need more explanation about pin reassignments.

Thank You Very Kindly,
Jim
Here is what you suggested ... but I added some LED test code.

[Ttelmah]

Yes. Forgot this (I often use use fast_io, and set the tris myself). Because the compiler doesn't 'know' what pin your UART it on, it doesn't handle TRIS for you. So you need to specify 'output_float' for the RX pin, and 'output_drive' for the TX pin.
Use fputc, rather than sending values directly to TXREG. You are not checking the buffer is empty before sending, so could overflow the UART. fputc does this for you.

Best Wishes

[Jim Oram]

Dear Ttelmah,
I tried as you suggested using fputc(char) ... but the program hangs right there. This is strange. Looking up fputc in the new PCW compiler manual on page 175 does not seem to have anything about fputc .

As suggested I am using:

[jeremiah]

[Ttelmah]

fputc needs a stream name. so you use:

[Jim Oram]

Hello Ttelmah,
The "hello world" is working, but now the SPI does not work.
Redirecting pin assignments seem to work.

Prior to adding the "hello world" the SPI WAS working.
So something is not right.... I thought I could use UART2 with pin assignments and SPI at the same time.
Your comments are most needed and appreciated.

Here is the whole code as constructed from helpful CCS forum comments:
// ---------- from CCS user forum - modified with test LEDs ------------
//
//Get rid of #use spi- Use it if you want streams, or software
//spi. Only use setup_spi, or #use, not both.

//Tell the compiler you want to use the hardware UART - note 'UART2'
//Only UART2 can be mapped to the pins you want. Might as well use the
//hardware since it is there!...

#include <18F26J50.h>
#FUSES wdt,noprotect //,HS
#use fast_io(C)
#use delay(clock=8000000,RESTART_WDT)
#byte OSCCON = 0x0FD3
#byte BAUDCON1 = 0x0F7E
#byte BAUDCON2 = 0x0F7C
#byte SPBRG1 = 0x0FB0 // low byte
#byte SPBRG2 = 0x0FAB // low byte
#byte SPBRGH1 = 0x0F7F // EUSART1 Baud Rate Generator Register High Byte
#byte SPBRGH2 = 0x0F7D // EUSART2 Baud Rate Generator Register High Byte
#byte SSP1CON1 = 0x0FC6

#pin_select TX2=PIN_C0 // I/O pin assignment:
#pin_select RX2=PIN_C1 // use Uart 2 connect to PIN_C0 and C1

#use rs232 (baud=4800,parity=N,UART2,bits=8,errors,stream=COMM2)

#define STREAM_ARRAY_SIZE 35 // array size yet to be used.
#define GRNLED PIN_B6
#define REDLED PIN_B7
#define SSPOV 6

int8 x; // Test program to sort out UART2 and SPI

void main(){
OSCCON = 0x70; // 8mhz
SPBRGH2 = 0; // Data sheet Page 329
SPBRG2 = 103; // 103;
BAUDCON2 = 0x00; // 0x08; BRG16 bit 3

SPBRGH1 = 0; //
SPBRG1 = 103; // 103;

setup_spi(SPI_MASTER | SPI_L_TO_H | spi_clk_div_16);

while(TRUE){
fputc('1',COMM2); // fputc to COMM2 works.
delay_ms(1);
printf("hello CCS\r\n");

// bit_clear(SSP1CON1, SSPOV); // clear any overflo, may not be needed.
// Hangs on the next line when uncommented:

// spi_write('X'); // write X to to the SPI pin 18. HANGS !

delay_ms(500);
for(x = 0 ; x < 3 ; x++){
output_low(GRNLED); // green led on.
delay_ms(100);
output_high(GRNLED); // green led off.
delay_ms(100);
}
}
}

Thanks Kindly,
Jim
_________________
Jim Oram

[jeremiah]

You should still simplify it. You are doing a lot of things that CCS can handle and you still have some code not needed to test out SPI and UART (such as WDT)

Also, please use "code" tags so your code is more readable. I don't have your chip to test on, but try this out:

[Jim Oram]

jeremiah,
Thank you for the test code. Most appreciated.
I used your code and included LEDs for DeBug.
The code hangs on spi_write('X') . (Green LED stays on)
The pin assignments work, and data appears on C0 and is sent to Comm Operator at 4800 baud through a MCP2200 USB chip.
The MCP2200 chip will offload the 18F chip when I load the TCP/IP stack with TLS. That is why I need USART2 and SPI at the same time.

[jeremiah]

What compiler revision are you using?

The next step would be to look at the LST file and see where the assembly for that spi_write call would hang up. Also, you might explicitly turn off any other peripherals using the same pins as your SPI interface

[Jim Oram]

Using Versions:
PCW versions:
IDE 4.138
PCB 4.138
PCM 4.141
PCH 4.141
_________________
Jim Oram

[Jim Oram]

jeremiah, here is the list for spi_write:

[Jim Oram]

jeremiah,
As far as I know, with this simple program, I do not have any extra
peripherals using the same pins as the SPI interface.
It seems that it is possible to get the spi running, or the uasrt2 running, but not both. Any ideas?

Thanks Kindly,
Jim
_________________
Jim Oram

[Ttelmah]

Stop talking to the registers...
This is the assembler approach, and is not needed/wanted. There are a few (very few) occasions, when accessing registers directly is wanted/needed. This is not one of them.

You are programming part of UART1. You must not do this, since UART1 uses the same pins as the SPI. This is why I had the line 'setup_uart(FALSE)', to make _sure_ UART1 was turned off, since otherwise it'll stop the SPI from working. This is the line missing from Jeremiah's code.