SERIAL I/O
11.2 Block description
11.2.10 CTS/RTS function
When the CTS function is selected, the signal input to the CTS
the transmit conditions.)
i
pin must be at “L” level. (This is one of
When the RTS function is selected, the RTS pin outputs the following signals:
i
(1) Clock synchronous serial I/O mode
When the receive enable bit (bit 2 at addresses 3516, 3D16, B516) = “0” (reception disabled), the RTS
pin outputs “H” level.
i
When the receive enable bit = “0” (reception disabled), the RTS
i
pin outputs “L” level by setting the
receive enable bit to “1,” or by reading the low-order byte of the UARTi receive buffer register.
When the receive enable bit = “1” (continuously reception), the RTS pin outputs “L” level by reading
i
the low-order byte of the UARTi receive buffer register.
When reception has started, the RTS pin outputs “H” level.
i
When an internal clock is selected (bit 3 at addresses 3016, 3816, B016 = “0”), do not select the RTS
function because the RTS output is undefined.
(2) UART mode
When the receive enable bit (bit 2 at addresses 3516, 3D16, B516) = “0” (reception disabled), the RTS
i
pin outputs “H” level.
When the receive enable bit = “0” (reception disabled), the RTS
i
pin outputs “L” level by setting the
receive enable bit to “1,” or by reading the low-order byte of the UARTi receive buffer register.
When the receive enable bit = “1” (continuously reception), the RTS pin outputs “L” level by reading
i
the low-order byte of the UARTi receive buffer register.
When reception has started, the RTS
i
pin outputs “H” level.
Selection of the CTS/RTS function depends on the following bits.
•CTS/RTS function select bit (bit 2 at addresses 3416, 3C16, B416: see Figure 11.2.3.)
•CTS/RTS enable bit (bit 4 at addresses 3416, 3C16, B416: see Figure 11.2.3.)
•CTS
•CTS
•CTS
0
1
2
/RTS
/RTS
/RTS
0
1
2
separate select bit (bit 0 at address AC16: see Figure 11.2.13.)
separate select bit (bit 1 at address AC16: see Figure 11.2.13.)
separate select bit (bit 4 at address AC16: see Figure 11.2.13.)
Table 11.2.1 lists the selection of the CTS/RTS function.
7905 Group User’s Manual Rev.1.0
11-19
RENESAS [ RENESAS TECHNOLOGY CORP ]
