Uart Commands; Ba�D Rate Generator - Holtek HT66F20 Manual

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
Transmitter Shift Register (TSR)
MSB
..............................
TX Register (TXR)
Data to be transmitted

UART Commands

There are both read and write commands for the UART Module. For reading and writing to registers
both command and address information is contained within a single byte. The format for reading and
writing is shown in the following table.
Command Type
Read FIFO
Read Register
Write FIFO
Write Register
UART Status and Control Registers
There are six registers associated with the UART function. The USR, UCR1, UCR2 and UCR3
registers control the overall function of the UART module, while the BRG register controls the Baud
rate. The actual data to be transmitted and received on the serial interface is managed through the
TXR/RXR data register.
A[2:0] Name Reset
00H USR 0000 �0��
0�H UCR� 0000 0×00
02H UCR2 0000 0000
03H BRG ×××× ××××
04H UCR3 0--- ----
05H~0�H Un�sed ---- ----
Rev. 2.50
LSB TX Pin RX Pin
Ba�d Rate
Generator
UART Data Transfer Scheme UART Data Transfer Scheme
Bit 7 Bit 6 Bit 5
0 0 0
0 0 0
0 0 0
0 0 0
Bit 7 Bit 6 Bit 5
PERR NF FERR
UARTEN BNO PREN
TXEN RXEN BRGH
BRG� BRG6 BRG5
URST — —
UART Register Summary
24�
Receiver Shift Register (RSR)
MSB
..............................
RX Register (RXR)
Data received
Bit 4 Bit 3 Bit 2 Bit 1
0 0 ×
� 0 A2 A�
0 � ×
� � A2 A�
Note: "×" here stands for don't care
Bit 4 Bit 3 Bit 2
OERR RIDLE RXIF
PRT STOPS TXBRK
ADDEN WAKE RIE
BRG4 BRG3 BRG2
— — —
Reserved
LSB
B�ffer 3
B�ffer 2
B�ffer �
Bit 0
× ×
A0
× ×
A0
Bit 1 Bit 0
TIDLE TXIF
RX8 TX8
TIIE TEIE
BRG� BRG0
— —
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