Maxim-integrated MAXQ Family Users Guide: MAXQ2000 Supplement Manual de usuario descargar pdf (Pagina 51)

ADDENDUM TO SECTION 10: SERIAL I/O (UART) MODULE

The MAXQ2000 provides up to two serial UART modules (Serial 0 and 1 in the 68-pin package, Serial 0 in the 56-pin package), which

operate as described in the MAXQ Family User’s Guide. Table 15 shows the associated pins and Table 16 shows the associated reg-

isters for these UARTs.

Serial UART Example: Asynchronous 10-Bit Output at 115,200 Baud

move SCON0.6, #1 ; Set to mode 1 (10-bit asynchronous)

move SCON0.4, #1 ; Enable receiver

move SMD0.1, #1 ; Baud rate = 16 x baud clock

move PR0, #45E8h ; PR0 = 2^21 * 115200 / 13.5MHz (crystal)

move SCON0.0, #0 ; Clear received character flag

move SCON0.1, #0 ; Clear transmit character flag

Loop1:

move Acc, #'0' ; Start with '0' character

move LC[0], #10 ; Transmit from '0'-'9'

Loop2:

move SBUF0, Acc ; Send character

Transmit:

move C, SCON0.1 ; Check transmit flag

jump NC, Transmit ; Wait for transmit to complete

move SCON0.1, #0 ; Clear transmit flag

add #1 ; Increment character by 1

djnz LC[0], Loop2

jump Loop1

MAXQ Family User’s Guide:

MAXQ2000 Supplement

PIN NUMBER

SERIAL UART FUNCTION

68-PIN 56-PIN

MULTIPLEXED WITH PORT PIN

Serial Port 0 Receive—RXD0 53 44 P7.1

Serial Port 0 Transmit—TXD0 52 43 P7.0

Serial Port 1 Receive—RXD1 36 — P5.2

Serial Port 1 Transmit—TXD1 37 — P5.3

Table 15. Serial UART Input and Output Pins

SCON0 M2[06h] Serial Port 0 Control Register. Serial port mode, receive enable, 9th bit control, and interrupt flags.

SBUF0 M2[07h] Serial Port 0 Data Buffer. Input and output data buffer.

SMD0 M2[08h] Serial Port 0 Mode Register. Controls baud rate, interrupt enable, and framing error detection.

PR0 M2[09h] Serial Port 0 Phase Register. Contains counter reload value for baud rate generation.

SCON1 M3[06h] Serial Port 1 Control Register. Serial port mode, receive enable, 9th bit control, and interrupt flags.

SBUF1 M3[07h] Serial Port 1 Data Buffer. Input and output data buffer.

SMD1 M3[08h] Serial Port 1 Mode Register. Controls baud rate, interrupt enable, and framing error detection.

PR1 M3[09h] Serial Port 1 Phase Register. Contains counter reload value for baud rate generation.

Table 16. Serial UART Control Registers

Maxim Integrated

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 92 93

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