TMPM330 - Keil

• Handshake function
Data write timing to transmit
buffer or shift register
(Note 1)
(Note 2)
Under development
TMPM330 (rev 0.4) 9-19
TMPM330
The CTS pin enables frame by frame data transmission so that overrun errors can be
prevented. This function can be enabled or disabled by SC0MOD0 .
When the CTS 0 pin is set to the “H” level, the current data transmission can be completed
but the next data transmission is suspended until the CTS 0 pin returns to the “L” level.
However in this case, the INTTX0 interrupt is generated, the next transmit data is requested
to the CPU, data is written to the transmit buffer, and it waits until it is ready to transmit data.
Although no RTS pin is provided, a handshake control function can be easily implemented
by assigning a port for the RTS function. By setting the port to “H” level upon completion of
data reception (in the receive interrupt routine), the transmit side can be requested to
suspend data transmission.
CTS
SIOCLK
TXDCLK
TXD
CTS
Transmit side
Fig. 9-6 Handshake Function
Fig. 9-7 CTS (Clear to Transmit) Signal Timing
If the CTS signal is set to “H” during transmission, the next data transmission is
suspended after the current transmission is completed.
Data transmission starts on the first falling edge of the TXDCLK clock after CTS is set to
“L.”
RXD
RTS (Any port)
Receive side
Transmission is
suspended during
this period ②
①
13 14 15 16 1 2 3 14 15 16 1 2 3
TXD bit 0
start bit
Serial Channel (SIO)