Fork of MODSERIAL that works with LPC4088
Fork of MODSERIAL by
Diff: example_dma.cpp
- Revision:
- 12:8c7394e2ae7f
- Parent:
- 11:a93a62eeeb9d
diff -r a93a62eeeb9d -r 8c7394e2ae7f example_dma.cpp --- a/example_dma.cpp Wed Nov 24 00:33:40 2010 +0000 +++ b/example_dma.cpp Thu Jan 20 11:57:32 2011 +0000 @@ -1,144 +1,144 @@ -#ifdef COMPILE_EXAMPLE_CODE_MODSERIAL_MODDMA - -/* - * To run this test program, link p9 to p10 so the Serial loops - * back and receives characters it sends. - */ - -#include "mbed.h" - -/* Note, this example requires that you also import into the Mbed - compiler the MODDMA project as well as MODSERIAL - http://mbed.org/users/AjK/libraries/MODDMA/latest - MODDMA.h MUST come before MODSERIAL.h */ -#include "MODDMA.h" // <--- Declare first -#include "MODSERIAL.h" // Flollowed by MODSERIAL - -DigitalOut led1(LED1); -DigitalOut led2(LED2); -DigitalOut led3(LED3); -DigitalOut led4(LED4); - -MODSERIAL pc(USBTX, USBRX); - -/* - * As experiement, you can define MODSERIAL as show here and see what - * effects it has on the LEDs. - * - * MODSERIAL uart(TX_PIN, RX_PIN, 512); - * With this, the 512 characters sent can straight into the buffer - * vary quickly. This means LED1 is only on briefly as the TX buffer - * fills. - * - * MODSERIAL uart(TX_PIN, RX_PIN, 32); - * With this, the buffer is smaller than the default 256 bytes and - * therefore LED1 stays on much longer while the system waits for - * room in the TX buffer. - */ -MODSERIAL uart(TX_PIN, RX_PIN); - -MODDMA dma; - -// This function is called when a character goes from the TX buffer -// to the Uart THR FIFO register. -void txCallback(void) { - led2 = !led2; -} - -// This function is called when TX buffer goes empty -void txEmpty(void) { - led2 = 0; - pc.puts(" Done. "); -} - -void dmaComplete(void) { - led1 = 1; -} - -// This function is called when a character goes into the RX buffer. -void rxCallback(void) { - led3 = !led3; - pc.putc(uart.getc()); -} - -int main() { - char s1[] = " *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* "; - int c = 'A'; - - // Tell MODSERIAL where the MODDMA controller is. - pc.MODDMA( &dma ); - - // Ensure the baud rate for the PC "USB" serial is much - // higher than "uart" baud rate below. - pc.baud( PC_BAUD ); - - // Use a deliberatly slow baud to fill up the TX buffer - uart.baud(1200); - - uart.attach( &txCallback, MODSERIAL::TxIrq ); - uart.attach( &rxCallback, MODSERIAL::RxIrq ); - uart.attach( &txEmpty, MODSERIAL::TxEmpty ); - - // Loop sending characters. We send 512 - // which is twice the default TX/RX buffer size. - - led1 = 0; - - // Send the buffer s using DMA channel 7 - pc.attach_dmaSendComplete( &dmaComplete ); - pc.dmaSend( s1, sizeof(s1), MODDMA::Channel_7 ); - - for (int loop = 0; loop < 512; loop++) { - uart.printf("%c", c); - c++; - if (c > 'Z') c = 'A'; - } - - led1 = 0; // Show the end of sending by switching off LED1. - - // End program. Flash LED4. Notice how LED 2 and 3 continue - // to flash for a short period while the interrupt system - // continues to send the characters left in the TX buffer. - - while(1) { - led4 = !led4; - wait(0.25); - } -} - -/* - * Notes. Here is the sort of output you can expect on your PC/Mac/Linux host - * machine that is connected to the "pc" USB serial port. - * - * *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* ABCDEFGHIJKLMNOPQRSTUVWXYZABCDE - * FGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZA - * BCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVW - * XYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRS - * TUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNO - * PQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJK - * LMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFG - * HIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQ Done. R - * - * Note how the DMA blocks the TX buffer sending under standard interrupt control. - * Not until the DMA transfer is complete will "normal" buffered TX sending resume. - * - * Of interest is that last "R" character after the system has said "Done." - * This comes from the fact that the TxEmpty callback is made when the TX buffer - * becomes empty. MODSERIAL makes use of the fact that the Uarts built into the - * LPC17xx device use a 16 byte FIFO on both RX and TX channels. This means that - * when the TxEmpty callback is made, the TX buffer is empty, but that just means - * the "last few characters" were written to the TX FIFO. So although the TX - * buffer has gone empty, the Uart's transmit system is still sending any remaining - * characters from it's TX FIFO. If you want to be truely sure all the characters - * you have sent have left the Mbed then call txIsBusy(); This function will - * return true if characters are still being sent. If it returns false after - * the Tx buffer is empty then all your characters have been sent. - * - * In a similar way, when characters are received into the RX FIFO, the entire - * FIFO contents is moved to the RX buffer, assuming there is room left in the - * RX buffer. If there is not, any remaining characters are left in the RX FIFO - * and will be moved to the RX buffer on the next interrupt or when the running - * program removes a character(s) from the RX buffer with the getc() method. - */ - -#endif +#ifdef COMPILE_EXAMPLE_CODE_MODSERIAL_MODDMA + +/* + * To run this test program, link p9 to p10 so the Serial loops + * back and receives characters it sends. + */ + +#include "mbed.h" + +/* Note, this example requires that you also import into the Mbed + compiler the MODDMA project as well as MODSERIAL + http://mbed.org/users/AjK/libraries/MODDMA/latest + MODDMA.h MUST come before MODSERIAL.h */ +#include "MODDMA.h" // <--- Declare first +#include "MODSERIAL.h" // Flollowed by MODSERIAL + +DigitalOut led1(LED1); +DigitalOut led2(LED2); +DigitalOut led3(LED3); +DigitalOut led4(LED4); + +MODSERIAL pc(USBTX, USBRX); + +/* + * As experiement, you can define MODSERIAL as show here and see what + * effects it has on the LEDs. + * + * MODSERIAL uart(TX_PIN, RX_PIN, 512); + * With this, the 512 characters sent can straight into the buffer + * vary quickly. This means LED1 is only on briefly as the TX buffer + * fills. + * + * MODSERIAL uart(TX_PIN, RX_PIN, 32); + * With this, the buffer is smaller than the default 256 bytes and + * therefore LED1 stays on much longer while the system waits for + * room in the TX buffer. + */ +MODSERIAL uart(TX_PIN, RX_PIN); + +MODDMA dma; + +// This function is called when a character goes from the TX buffer +// to the Uart THR FIFO register. +void txCallback(void) { + led2 = !led2; +} + +// This function is called when TX buffer goes empty +void txEmpty(void) { + led2 = 0; + pc.puts(" Done. "); +} + +void dmaComplete(void) { + led1 = 1; +} + +// This function is called when a character goes into the RX buffer. +void rxCallback(void) { + led3 = !led3; + pc.putc(uart.getc()); +} + +int main() { + char s1[] = " *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* "; + int c = 'A'; + + // Tell MODSERIAL where the MODDMA controller is. + pc.MODDMA( &dma ); + + // Ensure the baud rate for the PC "USB" serial is much + // higher than "uart" baud rate below. + pc.baud( PC_BAUD ); + + // Use a deliberatly slow baud to fill up the TX buffer + uart.baud(1200); + + uart.attach( &txCallback, MODSERIAL::TxIrq ); + uart.attach( &rxCallback, MODSERIAL::RxIrq ); + uart.attach( &txEmpty, MODSERIAL::TxEmpty ); + + // Loop sending characters. We send 512 + // which is twice the default TX/RX buffer size. + + led1 = 0; + + // Send the buffer s using DMA channel 7 + pc.attach_dmaSendComplete( &dmaComplete ); + pc.dmaSend( s1, sizeof(s1), MODDMA::Channel_7 ); + + for (int loop = 0; loop < 512; loop++) { + uart.printf("%c", c); + c++; + if (c > 'Z') c = 'A'; + } + + led1 = 0; // Show the end of sending by switching off LED1. + + // End program. Flash LED4. Notice how LED 2 and 3 continue + // to flash for a short period while the interrupt system + // continues to send the characters left in the TX buffer. + + while(1) { + led4 = !led4; + wait(0.25); + } +} + +/* + * Notes. Here is the sort of output you can expect on your PC/Mac/Linux host + * machine that is connected to the "pc" USB serial port. + * + * *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* *DMA* ABCDEFGHIJKLMNOPQRSTUVWXYZABCDE + * FGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZA + * BCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVW + * XYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRS + * TUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNO + * PQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJK + * LMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFG + * HIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQ Done. R + * + * Note how the DMA blocks the TX buffer sending under standard interrupt control. + * Not until the DMA transfer is complete will "normal" buffered TX sending resume. + * + * Of interest is that last "R" character after the system has said "Done." + * This comes from the fact that the TxEmpty callback is made when the TX buffer + * becomes empty. MODSERIAL makes use of the fact that the Uarts built into the + * LPC17xx device use a 16 byte FIFO on both RX and TX channels. This means that + * when the TxEmpty callback is made, the TX buffer is empty, but that just means + * the "last few characters" were written to the TX FIFO. So although the TX + * buffer has gone empty, the Uart's transmit system is still sending any remaining + * characters from it's TX FIFO. If you want to be truely sure all the characters + * you have sent have left the Mbed then call txIsBusy(); This function will + * return true if characters are still being sent. If it returns false after + * the Tx buffer is empty then all your characters have been sent. + * + * In a similar way, when characters are received into the RX FIFO, the entire + * FIFO contents is moved to the RX buffer, assuming there is room left in the + * RX buffer. If there is not, any remaining characters are left in the RX FIFO + * and will be moved to the RX buffer on the next interrupt or when the running + * program removes a character(s) from the RX buffer with the getc() method. + */ + +#endif