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Si4432 V1.0 RF MODULE interfacing with PIC MCU thru' SPI

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speedEC

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Dear all,

I need to interface Silicon Labs Si4432 v1.0 Module with PIC16F1938 thru' SPI module. I could not able to receive signal from Si4432.

The settings are follows:

Si4432 V1.0 RF MODULE: SILICON LABS
MCU - PIC16F1938 - 8 BIT MCU

HARDW(A)IRES CONNECTION:

GND - GND
GPIO_0 - 0 V - UNCONNECTED TO MCU
GPIO_1 - 2.90 V - UNCONNECTED TO MCU
GPIO_2 - 1.42 V - UNCONNECTED TO MCU
VDD - 2.90V (2 AA BATTERY)
SDO - 0V - CONNECTED TO MCU'S SDI
SDI - 0V - CONNECTED TO MCU'S SDO
SCLK - 0V - CONNECTED TO MCU'S SCLK
nSEL - 0V - CONNECTED TO MCU'S DIG I/O PIN
nIRQ - 0V - CONNECTED TO MCU'S INTERRUPT PIN
SDN - GND - Always ON
GND - GND

MCU:

1. RB0 - SET AS INPUT (TRISB0 = 1) for nIRQ interrupt
2. RC4 - SET AS INPUT (TRISC4 = 1) for SDI

3. MCU internal clock - 4 MHz
4. INTIE and SSPIE interrupts enabled and GIE set

SW CODE:

init SPI Module:

Code C - [expand]
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void init_SSP_Module(){
 SSPIE = 1;
 SSPIF = 0;
    
 // SSP STATUS Register
 SSPSTAT = 10000000; // 8 - SMP -> SPI data input sample bit - 1 = Input data sampled at end of       
                                //data output time
                                // 7 - CKE: SPI Clock Edge Select bit - 0 = Transmit occurs on transition from 
                                // Idle to active clock state
                        // 6-0 - USED FOR I2C ONLY
 
// SSP CONTROL 1 Register
SSPCON1 = 00100000; // 76 - READ ONLY 
            // 5 - SSPEN: Synchronous Serial Port Enable bit
            // 4 - CKP: Clock Polarity Select bit - 0 = Idle state for clock is a low level
            // SSPM<3:0>: Synchronous Serial Port Mode Select bits
            // 0000 = SPI Master mode, clock = FOSC/4
SSPCON3 = 00000000;     // 765 - READ ONLY
                        // 4 - BOEN: Buffer Overwrite Enable bit
            // 0123 - READ ONLY
RC2 = 1;            // pull nSEL (Si4432) pin High
 
}


Reading Si4432:

1. char ItStatus1;
2. ItStatus1 = SpiReadRegister(0x03); //read the Interrupt Status1 register

Code C - [expand]
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char SpiReadRegister (char reg)
{
RC2 = 0;      // set nSEL low
SSPBUF = reg; //write data into the SPI register;
while(SSPIF == 0);
 
SSPIF = 0;
SSPBUF = 0xFF; //write dummy data into the SPI register
while(SSPIF == 0);
 
SSPIF = 0;
 
RC2 = 1;
return SSPBUF;
}


Si4432 - Serial Peripheral Interface (SPI)

The Si4430/31/32 communicates with the host MCU over a standard 3-wire SPI interface: SCLK, SDI, and nSEL. The host MCU can read data from the device on the SDO output pin. A SPI transaction is a 16-bit sequence which consists of a Read-Write (R/W) select bit, followed by a 7-bit address field (ADDR), and an 8-bit data field (DATA) as demonstrated in Figure 3. The 7-bit address field is used to select one of the 128, 8-bit control registers. The R/W select bit determines whether the SPI transaction is a read or write transaction. If R/W = 1 it signifies a WRITE transaction, while R/W = 0 signifies a READ transaction. The contents (ADDR or DATA) are latched into the Si4430/31/32 every eight clock cycles. The timing parameters for the SPI interface are shown in Table 10. The SCLK rate is flexible with a maximum rate of 10 MHz.

any help?

thanks
pmk
 

Attachments

  • Si4432-chip-SPI-wireless-transceiver.jpg
    Si4432-chip-SPI-wireless-transceiver.jpg
    117.5 KB · Views: 99
  • Si4430-31-32.pdf
    2.2 MB · Views: 69

Added:

Silicon Labs' example code for reading Si4432: They have used C8501F93X MCU to communicate with Si4432.

They set:

CKPHA = 0; // CLOCK PHASE -> data centered on first edge of SCK period
CKPOL = 0; // POLARITY -> SCK line is low in idle state

NSS pin connected to nSEL pin of Si4432 RF (it is like SS pin in MCU to read/write SPI)

I set as:

CKE = 0; // Transmit occurs on transition from Idle to active clock state (rising edge)
CKP = 0; // Polarity -> SCK line is low in idle state
SMP = 1; // 1 = Input data sampled at end of data output time

I am receiving some data. I don't know whether it is valid data. But, I don't know the register settings of Si4432.

on Module 30 MHz clock used. Module works fine. But I could not able to read thru' SPI.

Also SCK timing is different in both datasheet. i.e PIC16F1938 and C8501F93X.

Any idea?

thanks
pmk
 

Attachments

  • SiliconLabs_sampleCode.png
    SiliconLabs_sampleCode.png
    19.3 KB · Views: 138
  • PIC16F1938_SPI_SCK.png
    PIC16F1938_SPI_SCK.png
    37.6 KB · Views: 100
  • C8501F93X_ SPI_1.png
    C8501F93X_ SPI_1.png
    45.7 KB · Views: 90
  • C8501F93X_ SPI_2.png
    C8501F93X_ SPI_2.png
    51.2 KB · Views: 94
  • C8501F93X_ SPI_SCK.png
    C8501F93X_ SPI_SCK.png
    16.5 KB · Views: 95

Problem with hardware. Solved the problem. It works fine now.

thanks
pmk
 

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