dyeatman
Joined: 06 Sep 2003
Posts: 1934
Location: Norman, OK
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| SC16IS752 UART I2C Routines Library |
 Posted: Sun Oct 26, 2008 8:35 pm |
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| Code: | ////////////////////////////////////////////////////////////////////////////////
// SC16IS752 UART Routines Library
//
// Filename : SC16IS752 UART I2C Routines.c
// Programmer : Dave Yeatman
// Version : 10/27/2008
// Remarks : This example provides framework code to communicate with
// the NXP SC16IS752 Dual Channel UART using I2C. This UART driver
// has been tested for both UART Channel 0 (A) and Channel 1 (B).
// The GPIO I/O functions have also been tested.
//
// More information on the UART can be found at www.NXP.com:
////////////////////////////////////////////////////////////////////////////////
//
// SC16IS752 Dual UART Register Defines
//
#define RHR 0x00 // Recv Holding Register is 0x00 in READ Mode
#define THR 0x00 // Xmit Holding Register is 0x00 in WRITE Mode
//
#define IER 0x01 // Interrupt Enable Register
//
#define IIR 0x02 // Interrupt Identification Register in READ Mode
#define FCR 0x02 // FIFO Control Register in WRITE Mode
//
#define LCR 0x03 // Line Control Register
#define MCR 0x04 // Modem Control Register
#define LSR 0x05 // Line status Register
#define MSR 0x06 // Modem Status Register
#Define SPR 0x07 // ScratchPad Register
#define TCR 0x06 // Transmission Control Register
#define TLR 0x07 // Trigger Level Register
#define TXLVL 0x08 // Xmit FIFO Level Register
#define RXLVL 0x09 // Recv FIFO Level Register
#define IODir 0x0A // I/O P:ins Direction Register
#define IOState 0x0B // I/O Pins State Register
#define IOIntEna 0x0C // I/O Interrupt Enable Register
#define IOControl 0x0E // I/O Pins Control Register
#define EFCR 0x0F // Extra Features Control Register
//
#define DLL 0x00 // Divisor Latch LSB 0x00
#define DLH 0x01 // Divisor Latch MSB 0x01
//
#define EFR 0x02 // Enhanced Function Register
//
#define I2CWRITE 0x00
#define I2CREAD 0x01
#define CHANA 0
#define CHANB 1
//
//***********************************************
byte ReadUART(int8 RegAddr, int1 CHAN) // Internal register address plus channel #(0 or 1)
{ // returns byte read from the UART register
byte data;
//
I2C_Start();
Delay_us(15);
I2C_write(UART_ADDR); // write cycle
I2C_write((RegAddr << 3) | (CHAN << 1)); // write cycle for reg address to selected channel
I2C_Start(); // restart
Delay_us(15);
I2C_write(UART_ADDR | I2CREAD); // read cycle
data=I2C_read(0);
I2C_Stop();
return(data);
}
//
//*********************************************
void WriteUART(int8 RegAddr, int1 CHAN, byte Data) // Internal register address plus channel #(0 or 1)
{ // sends data byte to selected UART register
I2C_Start();
Delay_us(15);
I2C_write(UART_ADDR); // write cycle
I2C_write((RegAddr << 3) | (CHAN << 1)); // write cycle
I2C_write(data);
I2C_Stop();
}
//
//*********************************************
void UART_Send_Char(int1 CHAN, byte Data) //channel #(0 or 1) plus the data byte to be sent
{ // send byte to UART Xmit via the I2C bus
WriteUART(THR, CHAN, Data); // send data to UART Transmit Holding Register
}
//
//*******************************************************
void Init_SC16IS752 (void)
{
// This init routine initializes ChannelS A and B
//
// Channel A Setups
//Prescaler in MCR defaults on MCU reset to the value of 1
WriteUART(LCR, CHANA, 0x80); // 0x80 to program baud rate divisor
WriteUART(DLL, CHANA, 0x18); // 0x18=9600K, 0x06 =38,42K with X1=3.6864MHz
WriteUART(DLH, CHANA, 0x00); //
//
WriteUART(LCR, CHANA, 0xBF); // access EFR register
WriteUART(EFR, CHANA, 0X10); // enable enhanced registers
//
WriteUART(LCR, CHANA, 0x03); // 8 data bits, 1 stop bit, no parity
WriteUART(FCR, CHANA, 0x07); // reset TXFIFO, reset RXFIFO, enable FIFO mode
// Channel B Setups
//Prescaler in MCR defaults on MCU reset to the value of 1
WriteUART(LCR, CHANB, 0x80); // 0x80 to program baud rate divisor
WriteUART(DLL, CHANB, 0x18); // 0x18=9600K, 0x06 =38,42K with X1=3.6864MHz
WriteUART(DLH, CHANB, 0x00); //
//
WriteUART(LCR, CHANB, 0xBF); // access EFR register
WriteUART(EFR, CHANB, 0X10); // enable enhanced registers
//
WriteUART(LCR, CHANB, 0x03); // 8 data bits, 1 stop bit, no parity
WriteUART(FCR, CHANB, 0x07); // reset TXFIFO, reset RXFIFO, enable FIFO mode
}
//
//*********************************************
char Poll_UART_RHR(CHAN)
{ // Poll UART to determine if data is waiting
char data = 0x00;
//
if (ReadUART(LSR, CHAN) & 0x01) // is data waiting??
{ // data present in receiver FIFO
data = ReadUART(RHR, CHAN);
}
// return received char or zero
return(data);
}
//
//*********************************************
void Set_GPIO_Dir(bits)
{ // Set Direction on UART GPIO Port pins GPIO0 to GPIO7
// 0=input 1=Output
WriteUART(IOControl, 0, 0x03); // Set the IOControl Register to GPIO Control
WriteUART(IODir,0, bits); // output the control bits to the IO Direction Register
}
//*********************************************
byte Read_GPIO()
{ // Read UART GPIO Port
char data = 0x00;
//
data=ReadUART(IOState,0); // get GPIO Bits state 0-7
// return data bits state or zero
return(data);
}
//
//*********************************************
void Write_GPIO(data)
{ // Load UART GPIO Port
WriteUART(IOState,0, data); // set GPIO Output pins state 0-7
}
//
//*********************************************
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