Uart
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The document discusses UART (Universal Asynchronous Receiver/Transmitter) which is a type of asynchronous receiver/transmitter hardware that translates data between parallel and serial forms. It describes UART components, protocols, and how to initialize and use UART methods for communication and debugging purposes using RS232 and MAX232 standards.
![UART->Initial Initial iboot uart_setup(); UartHasInit clock_gate_switch(UART_CLOCKGATE,ON); In boot mode, put the clock on, if done release the memory to operator system for(i = 0; i < NUM_UARTS; i++) { … } SET_REG(HWUarts[i].ULCON, UART_8BITS); Set register data to control each UART set uart_set_clk(i, UART_CLOCK_EXT_UCLK0); uart_set_sample_rate(i, 16); uart_set_flow_control(0, OFF); UARTs[i].fifo = ON; UartHasInit = TRUE; Check UARTinitial is ok or not](https://image.slidesharecdn.com/uart-100513001504-phpapp01/85/Uart-10-320.jpg)
Uart
- 1. UART 2010/05/13 by Sean Chen
- 2. What’s UART? How to use it ? UART Protocol UART components ARM 926-EJS Flow Chart How to control? UART->Initial UART->Methods How to implement/Debug? RS232 MAX232 IC
- 3. What’s UART? UART A universal asynchronous receiver/transmitter is a type of "asynchronous receiver/transmitter", a piece of computer hardware that translates data between parallel and serial forms. UARTs are commonly used in conjunction with other communication standards such as EIA RS-232 . Sample case RS232 Ref: http://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter
- 4. How to use it ? How With the UART, you can add an LCD, bootloading, bluetooth wireless , make a datalogger , debug code, test sensors , and much more! Key words Bootloading A boot sequence is the initial set of operations that the computer performs when power is switched on. The bootloader typically loads the main operating system for the computer. Datalogger A data logger (also datalogger or data recorder ) is an electronic device that records data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely Ref :http://www.societyofrobots.com/microcontroller_uart.shtml
- 5. UART Protocol Signal definition TX transmitter RX Receiver In asynchronous transmitting, teletype -style UARTs send a "start" bit, five to eight data bits, least-significant-bit first, an optional "parity" bit, and then one, one and a half, or two "stop" bits. The start bit is the opposite polarity of the data-line's idle state. The stop bit is the data-line's idle state, and provides a delay before the next character can start. (This is called asynchronous start-stop transmission). TX RX RX TX M1 M2
- 6. UART components A UART usually contains the following components: a clock generator, usually a multiple of the bit rate to allow sampling in the middle of a bit period. input and output shift registers transmit/receive control read/write control logic transmit/receive buffers (optional) parallel data bus buffer (optional) First-in, first-out ( FIFO ) buffer memory (optional) Ref :http://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter
- 7. ARM 926-EJS
- 8. Flow chart Flow chart Boot Initial Set the UART Check the UART is workable Configure setting …. Initial Done Release 2 operator system used or unused Receive Transmit
- 9. How to control ? Memory location // Devices#define UART 0x3CC00000 // Registers#define (offset) UART0 0x0 Register #define UART_UTXH 0x20 #define UART_URXH 0x24 Mode #define UART_UCON_RXMODE_SHIFT 0 #define UART_UCON_RXMODE_MASK (0x3 << UART_UCON_RXMODE_SHIFT) FIFO control #define UART_FIFO_RESET_TX 0x4 #define UART_FIFO_RESET_RX 0x2 #define UART_FIFO_ENABLE 0x1 UART Display 0x00010000 0x00040000 0x000F0000
- 10. UART->Initial Initial iboot uart_setup(); UartHasInit clock_gate_switch(UART_CLOCKGATE,ON); In boot mode, put the clock on, if done release the memory to operator system for(i = 0; i < NUM_UARTS; i++) { … } SET_REG(HWUarts[i].ULCON, UART_8BITS); Set register data to control each UART set uart_set_clk(i, UART_CLOCK_EXT_UCLK0); uart_set_sample_rate(i, 16); uart_set_flow_control(0, OFF); UARTs[i].fifo = ON; UartHasInit = TRUE; Check UARTinitial is ok or not
- 11. UART->Methods Methods int uart_write (int ureg, const char *buffer, uint32_t length); int uart_read (int ureg, char *buffer, uint32_t length, uint64_t timeout ); uint64_t timeout Define timeout to retry
- 12. MAX232 IC RS232 Test I/O PC host and console mode support
- 13. How to implement/Debug? RS232 In telecommunications , RS-232 (Recommended Standard 232) is a standard for serial binary single-ended data and control signals connecting between a DTE ( Data Terminal Equipment ) and a DCE ( Data Circuit-terminating Equipment ). It is commonly used in computer serial ports . A similar ITU-T standard is V.24 . RS232 pin-map table http://en.wikipedia.org/wiki/RS-232 MAX232 datasheet http://www.datasheetcatalog.com/datasheets_pdf/M/A/X/2/MAX232.shtml
- 14. RS232 serial cables pin-table http://www.lammertbies.nl/comm/cable/RS-232.html Console mode Linux (putty) http://www.vanemery.com/Linux/Serial/serial-console.html http://ed32.blogspot.com/2010/01/ubuntuputty.html