Transfer Data Settings - Epson S1C17001 Technical Manual

18 UART

18.4 Transfer Data Settings

Set the following conditions to set the transfer data format.
• Data length: 7 or 8 bits
• Start bit: Fixed at 1 bit
• Stop bit: 1 or 2 bits
• Parity bit: Even, odd, no parity
Note: Make sure the UART is halted (when RXEN/UART_CTL register = 0) before changing transfer
data format settings.
∗ RXEN: UART Enable Bit in the UART Control (UART_CTL) Register (D0/0x4104)
Data length
The data length is selected by CHLN (D4/UART_MOD register). Setting CHLN to 0 (default) sets the data
length to 7 bits. Setting CHLN to 1 sets the data length to 8 bits.
∗ CHLN: Character Length Select Bit in the UART Mode (UART_MOD) Register (D4/0x4103)
Stop bit
The stop bit length is selected by STPB (D1/UART_MOD register). Setting STPB to 0 (default) sets the stop
bit length to 1 bit. Setting STPB to 1 sets the stop bit length to 2 bits.
∗ STPB: Stop Bit Select Bit in the UART Mode (UART_MOD) Register (D1/0x4103)
Parity bit
Whether the parity function is enabled or disabled is selected by PREN (D3/UART_MOD register). Setting
PREN to 0 (default) disables the parity function. In this case, no parity bit is added to the transfer data and the
data is not checked for parity when received. Setting PREN to 1 enables the parity function. In this case, a par-
ity bit is added to the transfer data and the data is checked for parity when received.
When the parity function is enabled, the parity mode is selected by PMD (D2/UART_MOD register). Setting
PMD to 0 (default) adds a parity bit and checks for even parity. Setting PMD to 1 adds a parity bit and checks
for odd parity.
∗ PREN: Parity Enable Bit in the UART Mode (UART_MOD) Register (D3/0x4103)
∗ PMD: Parity Mode Select Bit in the UART Mode (UART_MOD) Register (D2/0x4103)
Sampling clock (sclk-1/16)
CHLN = 0, PREN = 0, STPB = 0
CHLN = 0, PREN = 1, STPB = 0
CHLN = 0, PREN = 0, STPB = 1
CHLN = 0, PREN = 1, STPB = 1
CHLN = 1, PREN = 0, STPB = 0
CHLN = 1, PREN = 1, STPB = 0
CHLN = 1, PREN = 0, STPB = 1
CHLN = 1, PREN = 1, STPB = 1
214
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
s1 D0 D1 D2
Figure 18.4.1: Transfer data format
EPSON
D3 D4 D5 D6 s2
D3 D4 D5 D6 p
D3 D4 D5 D6 s2
D3 D4 D5 D6 p
D3 D4 D5 D6 D7
D3 D4 D5 D6 D7
D3 D4 D5 D6 D7
D3 D4 D5 D6 D7
s1: Start bit, s2 & s3: Stop bits, p: Parity bit
S1C17001 TECHNICAL MANUAL
s2
s3
s2 s3
s2
p s2
s2 s3
p s2 s3