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welbertdeoliveira
Joined: 29 Aug 2022
Posts: 1
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| Renesas FS2012 + PIC16F877A I2C Issues |
 Posted: Mon Aug 29, 2022 11:32 am |
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Good afternoon.
I'm facing some problems for interface a Renesas FS2012 gas flow sensor with a PIC16F877A. The procedure for configuring the communication, based on the documentation is:
"To obtain data from the sensor, send START bit, slave address (0x07) and read bit (READ) to FS2012 and then read the two bytes of sensor data." (https://www.renesas.com/us/en/document/apn/fs2012-sample-application?language=en, page 10, "3.2 Sensor Functions").
I'm trying to configure the interface and obtain the MSB and LSB, and print on a 16x2 LCD. But, it's only possible to see FFh in both registers.
I can see the I2C protocol working by an oscilloscope.
Could anyone help me?
Best regards.
| Code: |
/*
-------------------------------------------------------------------------------------
Renesas FS2012 Gas Flow Sensor + display LCD 16x2
Biblioteca nativa do CCS C
Modo 4 bits
I/O no PortD
Conexoes físicas do LCD na PortD
lcd_enable_pin pin_B5
lcd_rs_pin pin_B4
lcd_rw_pin pin_B3
lcd_data4 pin_D4
lcd_data5 pin_D5
lcd_data6 pin_D6
lcd_data7 pin_D7
-------------------------------------------------------------------------------------
*/
#include <16F877A.h>
#use delay(clock = 4000000)
#use I2C(master, fast = 100000, sda = pin_C4, scl = pin_C3)
#fuses XT, NOWDT, PUT, NOLVP
#define lcd_rs_pin pin_B5
#define lcd_rw_pin pin_B4
#define lcd_enable_pin pin_B3
#define lcd_data4 pin_D4
#define lcd_data5 pin_D5
#define lcd_data6 pin_D6
#define lcd_data7 pin_D7
#define sensor_address 0x07
#include <lcd.c>
unsigned int8 dado_H, dado_L = 0;
void main()
{
// Habilita o LCD e imprime mensagens iniciais
lcd_init();
lcd_putc('\f');
delay_ms(100);
while(true)
{
i2c_start();
i2c_write(sensor_address);
i2c_write(1);
i2c_start();
i2c_write(sensor_address);
dado_H = i2c_read(1);
dado_L = i2c_read(0);
i2c_stop();
lcd_gotoxy(1,1);
lcd_putc("MSB: ");
lcd_gotoxy(6,1);
printf(lcd_putc, "%X", dado_H);
lcd_gotoxy(1,2);
lcd_putc("LSB: ");
lcd_gotoxy(6,2);
printf(lcd_putc, "%X", dado_L);
}
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Aug 29, 2022 3:17 pm |
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The FS2012 data sheet lists 0x07 as the slave address. That's in 7-bit format.
However, CCS i2c routines use 8-bit format, so double that to 0x0E.
Then we get:
i2c read address: 0x0E
i2c write address: 0x0F
--------------------------------------
Also, your i2c read data routine needs to be changed to this:
| Quote: | i2c_start();
i2c_write(SENSOR_WRITE_ADDRESS); // 0x0F
i2c_write(1);
i2c_start();
i2c_write(SENSOR_READ_ADDRESS); // 0x0E
dado_H = i2c_read(1);
dado_L = i2c_read(0);
i2c_stop();
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Ttelmah
Joined: 11 Mar 2010
Posts: 19506
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| Posted: Wed Aug 31, 2022 1:24 am |
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It is slightly worrying that the device is using a reserved address.
In 7bit addresses 0 to 7, and 78 to 7F are legally reserved addresses.
Devices are not meant to use these. 7 is actually reserved as the speed
control address value.
The I2C valid 7bit device addresses are 8 to 77.
That a device is being sold that uses one of the reserved addresses, is
'scary'...  |
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