📄 fet140_dma_15.c
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//******************************************************************************
// MSP-FET430P140 Demo - DMA0/1/2, USART0 SPI 3-Wire SPI Slave P1.x Exchange
//
// Description: SPI Master communicates at fast as possible, full-duplex with
// SPI Slave using 3-wire mode. The level on P1.4/5 is TX'ed and RX'ed to P1.0
// and P1.1. Master will pulse slave Reset on init to insure synch start.
// With data transfer driven directly by DMA - no CPU resources used.
// DMA0 trigger from TX read, which uses MPY to shift read P1 left
// DMA1 trigger from MPY moves shifted P1 data to the USART0 TX buffer
// DMA2 trigger from USART0 RX buffer moves received data to P1
// Slave normal mode is LPM4.
// ACLK = n/a, MCLK = SMCLK = DCO ~ 800kHz, ULCK = external
// //* Final Production MSP430F16x(x) Device Required *//
//
// fet140_dma_15 fet140_dma_14
// MSP430F169 Slave MSP430F169 Master
// ----------------- -----------------
// | XIN|- /|\| XIN|-
// | | | | |
// | XOUT|- --|RST XOUT|-
// | | /|\ | |
// | RST|--+<----|P3.0 |
// LED <-|P1.0 | | P1.4|<-
// LED <-|P1.1 | | P1.5|<-
// ->|P1.4 | | P1.0|-> LED
// ->|P1.5 | | P1.1|-> LED
// | SIMO0/P3.1|<-------|P3.1/SIMO0 |
// | SOMI0/P3.2|------->|P3.2/SOMI0 |
// | UCLK/P3.3|<-------|P3.3/UCLK |
//
// M. Buccini / A. Dannenberg
// Texas Instruments Inc.
// November 2005
// Built with IAR Embedded Workbench Version: 3.30A
//******************************************************************************
#include <msp430x16x.h>
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog
P1OUT = 0x00; // P1.0 setup for LED output
P1DIR |= 0x03;
P3SEL |= 0x0E; // P3.1,2,3 SPI option select
U0CTL = CHAR + SYNC + SWRST; // 8-bit, SPI
U0TCTL = CKPL + STC; // Polarity, 3-wire
U0BR0 = 0x02; // SPICLK = SMCLK/2
U0BR1 = 0x00;
U0MCTL = 0x00;
ME1 |= USPIE0; // Module enable
U0CTL &= ~SWRST; // SPI enable
MPY = 0x1000; // MPY first operand
// Setup triggers first
DMACTL0 = DMA2TSEL_3 + DMA1TSEL_11 + DMA0TSEL_4; // URXIFG0, MPY, UTXIFG0
// TX load
DMA1SA = RESHI_; // Src address = multiplier
DMA1DA = U0TXBUF_; // Dst address = RAM memory
DMA1SZ = 1; // Size in bytes
DMA1CTL = DMADT_4 + DMASBDB + DMAEN; // Sng, config
// TX Init
DMA0SA = P1IN_; // Src address
DMA0DA = OP2_; // Dst address = multiplier
DMA0SZ = 1; // Size in words
DMA0CTL = DMADT_4 + DMASBDB + DMALEVEL + DMAEN; // Sng rpt, config
// RX Store
DMA2SA = U0RXBUF_; // Src address = UART RX Buffer
DMA2DA = P1OUT_; // Dst address = P1
DMA2SZ = 1; // Size in bytes
DMA2CTL = DMADT_4 + DMASBDB + DMAEN; // Sng, config
_BIS_SR(LPM4_bits + GIE); // Enter LPM4 w/ interrupt
}
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