Andrew Boyson / oldheating

Central Heating controller using the real time clock, PHY module for internet, 1-wire interface for temperature sensors, a system log and a configuration file

Dependencies:   net 1-wire lpc1768 crypto clock web fram log

/media/uploads/andrewboyson/heating.sch

/media/uploads/andrewboyson/heating.brd

/media/uploads/andrewboyson/eagle.epf

main/spi.c@1:ccc66fdf858d, 2018-01-28 (annotated)

Committer:
andrewboyson
Date:
Sun Jan 28 14:41:12 2018 +0000
Revision:
1:ccc66fdf858d
Parent:
0:3c04f4b47041
Child:
5:82197a6997fd
Updated libraries

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 1:ccc66fdf858d 1 #include "defs.h"
andrewboyson 0:3c04f4b47041 2 #include "log.h"
andrewboyson 0:3c04f4b47041 3
andrewboyson 0:3c04f4b47041 4 #define CS_BIT_MASK_0 1 << 6 //pin 0.6
andrewboyson 0:3c04f4b47041 5
andrewboyson 0:3c04f4b47041 6 void SpiInit(void)
andrewboyson 1:ccc66fdf858d 7 {
andrewboyson 0:3c04f4b47041 8 //Configure
andrewboyson 0:3c04f4b47041 9 LPC_SSP1->CR0 |= 7 << 0; //3:0 8 bit transfer
andrewboyson 0:3c04f4b47041 10 LPC_SSP1->CR0 |= 0 << 4; //5:4 SPI
andrewboyson 0:3c04f4b47041 11 LPC_SSP1->CR0 |= 0 << 6; //7:6 Mode 0
andrewboyson 0:3c04f4b47041 12 LPC_SSP1->CR0 |= 0 << 8; //divide by 1
andrewboyson 0:3c04f4b47041 13
andrewboyson 0:3c04f4b47041 14 //Set prescaler bps = PCLK / PS ==> PS = PCLK / bps ==> PS = 96/16 = 6
andrewboyson 0:3c04f4b47041 15 LPC_SSP1->CPSR = 6; //Bit 0 must be 0. 6 ==> 16 bps which is within the 20MHz allowed by the FRAM
andrewboyson 0:3c04f4b47041 16
andrewboyson 0:3c04f4b47041 17 //Select the function of the ssel pin: P0.6
andrewboyson 0:3c04f4b47041 18 LPC_PINCON->PINSEL0 &= ~0x3000;
andrewboyson 0:3c04f4b47041 19 LPC_PINCON->PINSEL0 |= 0x0000; // table 80. 13:12 = 0b00 ==> GPIO
andrewboyson 0:3c04f4b47041 20 LPC_PINCON->PINMODE0 &= ~0x3000; // table 88. 13:12 = 0b00 ==> enable pull-up resistor
andrewboyson 0:3c04f4b47041 21 LPC_GPIO0->FIODIR |= CS_BIT_MASK_0; //Set the direction to 1 == output
andrewboyson 0:3c04f4b47041 22 LPC_GPIO0->FIOSET = CS_BIT_MASK_0; //Deselect the output == CS = 1
andrewboyson 0:3c04f4b47041 23
andrewboyson 0:3c04f4b47041 24 //Select the function of the sck, miso and mosi pins: P0.7, P0.8 and P0.9
andrewboyson 0:3c04f4b47041 25 LPC_PINCON->PINSEL0 &= ~0xFC000;
andrewboyson 0:3c04f4b47041 26 LPC_PINCON->PINSEL0 |= 0xA8000; // table 80. 15:14, 17:16, 19:18 = 0b10
andrewboyson 0:3c04f4b47041 27 LPC_PINCON->PINMODE0 &= ~0xFC000; // table 88. = 0b00 ==> enable pull-up resistor
andrewboyson 0:3c04f4b47041 28
andrewboyson 0:3c04f4b47041 29 //Enable operation
andrewboyson 0:3c04f4b47041 30 LPC_SSP1->CR1 |= 2; //Enable the SSP controller
andrewboyson 0:3c04f4b47041 31 }
andrewboyson 0:3c04f4b47041 32 void SpiChipSelect(int value)
andrewboyson 0:3c04f4b47041 33 {
andrewboyson 0:3c04f4b47041 34 if (value) LPC_GPIO0->FIOSET = CS_BIT_MASK_0;
andrewboyson 0:3c04f4b47041 35 else LPC_GPIO0->FIOCLR = CS_BIT_MASK_0;
andrewboyson 0:3c04f4b47041 36 }
andrewboyson 0:3c04f4b47041 37 void SpiWrite(char byte)
andrewboyson 0:3c04f4b47041 38 {
andrewboyson 0:3c04f4b47041 39 LPC_SSP1->DR = byte; //This loads the next frame in the TX FIFO
andrewboyson 0:3c04f4b47041 40 }
andrewboyson 0:3c04f4b47041 41 int SpiBusy(void)
andrewboyson 0:3c04f4b47041 42 {
andrewboyson 0:3c04f4b47041 43 return LPC_SSP1->SR & 0x10; //bit 4 is BSY. This bit is 0 if the SSPn controller is idle, or 1 if it is currently sending/receiving a frame and/or the Tx FIFO is not empty.
andrewboyson 0:3c04f4b47041 44 }
andrewboyson 0:3c04f4b47041 45 char SpiRead(void)
andrewboyson 0:3c04f4b47041 46 {
andrewboyson 0:3c04f4b47041 47 return LPC_SSP1->DR & 0xFF; //This reads the oldest frame in the RX FIFO
andrewboyson 0:3c04f4b47041 48 }
andrewboyson 0:3c04f4b47041 49 char SpiTransfer(char byte)
andrewboyson 0:3c04f4b47041 50 {
andrewboyson 0:3c04f4b47041 51 SpiWrite(byte);
andrewboyson 0:3c04f4b47041 52 while(SpiBusy()) /*spin until not busy, at 16 bits per us or 2 bytes per us should be only 48 operations*/;
andrewboyson 0:3c04f4b47041 53 return SpiRead();
andrewboyson 0:3c04f4b47041 54 }