GMS97C2051 Datasheet, PDF (7/39 Pages) Hynix Semiconductor – 8-Bit CMOS Microcontorller

8-Bit CMOS Microcontorller
Figure 3. Time/Counter 0 and 1 Input Clock Logic
fosc

12
P3.4/T0
P3.5/T1
max fosc/24
TR 0/1
TCON
Gate
=1
TMOD
P3.2/INT0
P3.3/INT1
C/T
TMOD
0
1
&
1
GMS97C2051/L2051
fosc/12
Control
Timer 0/1
Input Clock
Serial Interface (USART)
The serial port is full duplex, meaning it can trans-
mit and receive simultaneously. And it can operate
in four modes (one synchronous mode, three asyn-
chronous mode) as illustrated in table 5. The possi-
Table 5. USART Operating Modes
Mode
0
SCON
SM0 SM1
0
0
Baud Rate
fosc / 12
( fixed )
1
0
1
Set by Timer
( variable )
2
1
0
fosc / 64 or fosc / 32
( fixed )
3
1
1 Set by Timer
( variable )
ble baud rates can be calculated using the formulas
given in table 6.
Description
Shift Register
: Serial data enters and exits through RXD.
TXD outputs the shift clock.
Eight data bits are transmitted / received,
with the LSB first.
8-bit UART
: Ten bits are transmitted through TXD, or

received through RXD
a start bit (0), 8 data bits (LSB first),
and a stop bit (1)
9-bit UART
: Eleven bits are transmitted through TXD,

or received through RXD
a start bit (0), 8 data bits (LSB first),
a programmable ninth data bit ,
and a stop bit (1)
9-bit UART
: The same as Mode 2 except the variable
baud rate.
7
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