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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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 Posted: Sat Mar 31, 2012 8:35 pm |
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Did you buy a evaluation board for the TDC chip ? Or did you build it
yourself ? If you bought the board, then post a link to the webpage for it.
Post a list of your connections between the PIC and the TDC chip.
This appnote has a complete program on page 23. It could be translated
to CCS.
http://www.acam.de/fileadmin/Download/pdf/English/AN029_en.pdf
They have a little section near the start of the code that does what
you want. It tests if you can Read/write to the chip. It's commented out
in their code because it's only a test. It's called:
| Quote: |
read-write communication test
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They do not have any printf code to show the results.
Your posted code is only a snippet or a code fragment. The TDC
requires a full test program to make it work. I don't know if you
understand that.
For example, at the start of their test program, they do this:
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gp21_send_1byte(0x50); // Power on Reset to GP21
Dly100us((void*)5); // 500 us wait for GP21
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I doubt if you have this in your program.
Their example code appears to use an STM32 microcontroller and C
compiler. I will look at this code later and see if I can translate enough
of it to make a minimal test program. I can't do it now. Maybe tomorrow. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Apr 01, 2012 4:42 pm |
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I translated the R/W test code from the following TDC-GP21 appnote:
http://www.acam.de/fileadmin/Download/pdf/English/AN029_en.pdf
I translated the first few lines of main(), and also the necessary
support routines to do the R/W test. The example code starts on page 23.
The R/W test is described on page 19 of the data sheet, in this section:
3.1 Configuration registers
http://www.acam.de/fileadmin/Download/pdf/English/DB_GP21_en.pdf
The following code assumes that your hardware is all correct. I don't
have the TDC-GP21 chip or the Eval board to test this code, but I think it
has a good chance to work.
| Code: |
#include <16F887.h>
#fuses INTRC_IO,NOWDT,PUT,NOLVP
#use delay(clock=4M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#define SSEL PIN_C0
#define SPI_MODE_0 (SPI_L_TO_H | SPI_XMIT_L_TO_H)
#define SPI_MODE_1 (SPI_L_TO_H)
#define SPI_MODE_2 (SPI_H_TO_L)
#define SPI_MODE_3 (SPI_H_TO_L | SPI_XMIT_L_TO_H)
//---------------------------------------------
void gp21_send_1byte (int8 gp21_opcode_byte)
{
output_low(SSEL);
spi_write(gp21_opcode_byte);
output_high(SSEL);
}
//---------------------------------------------
void gp21_wr_config_reg (int8 opcode_address, int32 config_reg_data)
{
int8 Data_Byte_Lo;
int8 Data_Byte_Mid1;
int8 Data_Byte_Mid2;
int8 Data_Byte_Hi;
Data_Byte_Lo = config_reg_data;
Data_Byte_Mid1 = config_reg_data >> 8;
Data_Byte_Mid2 = config_reg_data >> 16;
Data_Byte_Hi = config_reg_data >> 24;
output_low(SSEL);
spi_write(opcode_address); // RAM WR OPCODE+ADDRESS
spi_write(Data_Byte_Hi); // DATA BYTE HIGH
spi_write(Data_Byte_Mid2); // DATA MID - 2
spi_write(Data_Byte_Mid1); // DATA MID - 1
spi_write(Data_Byte_Lo); // DATA LOW
output_high(SSEL);
}
//-----------------------------------------------
int32 gp21_read_4bytes(int8 read_opcode_addr)
{
int32 Result_read;
Result_read=0;
//.............. Result word = 4 Byte = 32 bits......................
output_low(SSEL);
spi_write(read_opcode_addr); // READ OPCODE + Address 1
//Reading byte1
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte2
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte3
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte4
Result_read |= spi_read(0xFF);
output_high(SSEL);
return Result_read;
}
//==========================================
void main()
{
int32 result;
printf("Start \n\r");
setup_spi(SPI_MASTER | SPI_MODE_1 | SPI_CLK_DIV_4);
output_high(SSEL); // Initialize Slave Select to inactive level
delay_ms(100);
gp21_send_1byte(0x50); // Power on Reset to GP21
delay_us(500); // 500 us wait for GP21
//----------- read-write communication test --------------
gp21_wr_config_reg(0x81, 0xABCDEF34); // Config reg 1
// Opcode 0xB5: Read content of highest 8 Bits of write
// register 1, to be used for testing the communication.
result = gp21_read_4bytes(0xB5);
printf("R/W Test result = %lx \n\r", result);
while(1);
}
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Sun Apr 01, 2012 10:08 pm |
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| PCM programmer wrote: | I translated the R/W test code from the following TDC-GP21 appnote:
http://www.acam.de/fileadmin/Download/pdf/English/AN029_en.pdf
I translated the first few lines of main(), and also the necessary
support routines to do the R/W test. The example code starts on page 23.
The R/W test is described on page 19 of the data sheet, in this section:
3.1 Configuration registers
http://www.acam.de/fileadmin/Download/pdf/English/DB_GP21_en.pdf
The following code assumes that your hardware is all correct. I don't
have the TDC-GP21 chip or the Eval board to test this code, but I think it
has a good chance to work.
| Code: |
#include <16F887.h>
#fuses INTRC_IO,NOWDT,PUT,NOLVP
#use delay(clock=4M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#define SSEL PIN_C0
#define SPI_MODE_0 (SPI_L_TO_H | SPI_XMIT_L_TO_H)
#define SPI_MODE_1 (SPI_L_TO_H)
#define SPI_MODE_2 (SPI_H_TO_L)
#define SPI_MODE_3 (SPI_H_TO_L | SPI_XMIT_L_TO_H)
//---------------------------------------------
void gp21_send_1byte (int8 gp21_opcode_byte)
{
output_low(SSEL);
spi_write(gp21_opcode_byte);
output_high(SSEL);
}
//---------------------------------------------
void gp21_wr_config_reg (int8 opcode_address, int32 config_reg_data)
{
int8 Data_Byte_Lo;
int8 Data_Byte_Mid1;
int8 Data_Byte_Mid2;
int8 Data_Byte_Hi;
Data_Byte_Lo = config_reg_data;
Data_Byte_Mid1 = config_reg_data >> 8;
Data_Byte_Mid2 = config_reg_data >> 16;
Data_Byte_Hi = config_reg_data >> 24;
output_low(SSEL);
spi_write(opcode_address); // RAM WR OPCODE+ADDRESS
spi_write(Data_Byte_Hi); // DATA BYTE HIGH
spi_write(Data_Byte_Mid2); // DATA MID - 2
spi_write(Data_Byte_Mid1); // DATA MID - 1
spi_write(Data_Byte_Lo); // DATA LOW
output_high(SSEL);
}
//-----------------------------------------------
int32 gp21_read_4bytes(int8 read_opcode_addr)
{
int32 Result_read;
Result_read=0;
//.............. Result word = 4 Byte = 32 bits......................
output_low(SSEL);
spi_write(read_opcode_addr); // READ OPCODE + Address 1
//Reading byte1
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte2
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte3
Result_read |= spi_read(0xFF);
Result_read = Result_read << 8;
//Reading byte4
Result_read |= spi_read(0xFF);
output_high(SSEL);
return Result_read;
}
//==========================================
void main()
{
int32 result;
printf("Start \n\r");
setup_spi(SPI_MASTER | SPI_MODE_1 | SPI_CLK_DIV_4);
output_high(SSEL); // Initialize Slave Select to inactive level
delay_ms(100);
gp21_send_1byte(0x50); // Power on Reset to GP21
delay_us(500); // 500 us wait for GP21
//----------- read-write communication test --------------
gp21_wr_config_reg(0x81, 0xABCDEF34); // Config reg 1
// Opcode 0xB5: Read content of highest 8 Bits of write
// register 1, to be used for testing the communication.
result = gp21_read_4bytes(0xB5);
printf("R/W Test result = %lx \n\r", result);
while(1);
}
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Hi, I have read the same document you posted. I wrote test code just like yours. I did sent 0x50 to the chip. I tried to write in reg0 and the read from it after 10ms delay, but I get 0. I have a question about your define of spi mode. Do I need to do all of them (mode0 to mode3)? Seems like you have 4 modes. When sending spi which mode it will use? I read about their datasheet and I think it should be SPI_L_TO_H. I think our team had tried to put 5V on the chip before. Maybe that burned the chip. I will keep trying. Thanks for your help. |
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Sun Apr 01, 2012 10:15 pm |
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| I didn't buy the board for the tdc chip. I bought an adapter for it such that I can place it on the breadboard. I built the oscillator to it like the one in the example application note. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Apr 01, 2012 11:30 pm |
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The setup_spi() statement clearly shows which SPI mode is used by
the program:
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setup_spi(SPI_MASTER | SPI_MODE_1 | SPI_CLK_DIV_4);
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The four #define statements for the SPI modes are there for reference. |
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Mon Apr 02, 2012 2:01 pm |
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Hi, I tried your code and I read 0 for the result. I suspected the chip is burned. I just replaced with another one today and try again. I still read 0. In the datasheet http://www.acam.de/uploads/media/DB_GP21_en_02.pdf
2-4 first table Serial Interface it mentions timing for fck at 3.3v is 20MHz. Does it matter? Since I am using 4 MHz internal clock of the pic, and the maximum internal frequency of PIC16f887 is 8Mhz. I think I read it somewhere that spi clock can be slow. It does not have to be fast. Thanks for helping and the test code. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Apr 02, 2012 2:09 pm |
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20 MHz is the maximum SPI clock frequency. We are not using anything
close to that high. It's not a problem.
Do you have all the required external circuits ? Such as the 4 MHz
external crystal and associated capacitors and resistors ?
I think it would have been easier if you bought the Evalution board. |
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Mon Apr 02, 2012 2:14 pm |
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Yes we have build the external circuit including 4 MHz, 3.2kHz
external crystal and associated capacitors and resistors. I will try to call the chip company for further assistant. According to the datasheet and application note I have, it should work. But now I don't think I ever wrote in the chip's registers, or able to read from it. Thanks for the help. I will post further info if I get something back from the chip company |
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cheeloh1
Joined: 24 Mar 2012
Posts: 3
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Apr 02, 2012 9:38 pm |
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| Quote: |
TDC only supports:
Clock Phase Bit = 1
Clock Polarity Bit = 0
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These settings are handled by the setup_spi() function when you specify
SPI_MODE_1 as the mode parameter. |
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Tue Apr 03, 2012 4:18 pm |
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Hi, I have a question. For your code
| Code: | | #use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS) |
I remember you said that setup_spi can only use the physical pin, which is PIN_C5(SDO) and PIN_C4(SDI). Should I use your define xmit pin and rcv pin? I use pin_c5 as serial data out and I can measure the data out using a oscilloscope. I didn't use C6 and C7. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Apr 03, 2012 5:09 pm |
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That's the UART module, and it's used for RS-232 communication.
It is not the same as the SSP module, which is used for SPI.
These are two separate modules, for different purposes, and they use
different pins from each other. |
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searuff
Joined: 22 Mar 2012
Posts: 13
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| Posted: Wed Apr 04, 2012 3:01 pm |
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| I called that company today and figure out the problem. It's the rst pin of the TDC chip. I have to send it to low to reset one time before using the spi interface. I hook it to high before since it's active low. But seems like in fast i need to manually reset it once. It's not written in the sample code so we all miss that. Thanks for everyone's help. |
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