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Clock asynchronous serial I/O (UART) mode
Mitsubishi microcomputers
M16C / 62 Group (80-pin)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
108
Example of receive timing when transfer data is 8 bits long (parity disabled, one stop bit)
Figure 1.14.18. Typical receive timing in UART mode
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(a) Separate CTS/RTS pins function (UART0)
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Setting the CTS/RTS separate bit (bit 6 of address 03B016) to “1” inputs/outputs the CTS signal and
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RTS signal from different pins. Choose which to use, CTS or RTS, by use of the CTS/RTS function
select bit (bit 2 of address 03A416). This function is effective in UART0 only. With this function cho-
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sen, the user cannot use the CTS/RTS function. Set "0" both to the CTS/RTS function select bit (bit
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2 of address 03AC16) and to the CTS/RTS disable bit (bit 4 of address 03AC16).
(b) Sleep mode (UART0, UART1)
This mode is used to transfer data between specific microcomputers among multiple microcomputers
connected using UARTi. The sleep mode is selected when the sleep select bit (bit 7 at addresses
03A016, 03A816) is set to “1” during reception. In this mode, the unit performs receive operation when
the MSB of the received data = “1” and does not perform receive operation when the MSB = “0”.
D0
Start bit
Sampled “L”
Receive data taken in
BRGi count
source
Receive enable bit
RxDi
Transfer clock
Receive
complete flag
RTSi
Stop bit
“1”
“0”
“1”
“H”
“L”
The above timing applies to the following settings :
Parity is disabled.
One stop bit.
RTS function is selected.
Receive interrupt
request bit
“0”
“1”
Transferred from UARTi receive register to
UARTi receive buffer register
Reception triggered when transfer clock
is generated by falling edge of start bit
D7
D1
Cleared to “0” when interrupt request is accepted, or cleared by software
Note: RTS in UART2 is not connected to the outside.
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Figure 1.14.19. The separate CTS/RTS pins function usage
Microcomputer
TXD0 (P63)
RXD0 (P62)
IN
OUT
CTS
RTS
CTS0 (P64)
RTS0 (P60)
IC
Note : The user cannot use CTS and RTS at the same time.