M38062M3-156FP MITSUBISHI [Mitsubishi Electric Semiconductor], M38062M3-156FP Datasheet - Page 21

• Manufacturer Part Number: M38062M3-156FP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Fig. 13 Operation of UART serial I/O function
Serial I/O1 control register (SIO1CON) 001A
The serial I/O control register consists of eight control bits for the
serial I/O function.
UART control register (UARTCON) 001B
The UART control register consists of four control bits (bits 0 to 3)
which are valid when asynchronous serial I/O is selected and set
the data format of an data transfer. One bit in this register (bit 4) is
always valid and sets the output structure of the P4
Serial I/O1 status register (SIO1STS) 0019
The read-only serial I/O1 status register consists of seven flags
(bits 0 to 6) which indicate the operating status of the serial I/O
function and various errors.
Three of the flags (bits 4 to 6) are valid only in UART mode.
The receive buffer full flag (bit 1) is cleared to “0” when the receive
buffer is read.
If there is an error, it is detected at the same time that data is
transferred from the receive shift register to the receive buffer, and
the receive buffer full flag is set. A write to the serial I/O status reg-
ister clears all the error flags OE, PE, FE, and SE (bit 3 to bit 6, re-
Transmit or receive clock
Transmit buffer write
Receive buffer read
Serial output T
Serial input R
Notes
1: Error flag detection occurs at the same time that the RBF flag becomes "1" (at 1st stop bit, during reception).
2: The transmit interrupt (TI) can be selected to occur when either the TBE or TSC flag becomes "1", depending on the setting of the transmit interrupt
3: The receive interrupt (RI) is set when the RBF flag becomes "1".
4: After data is written to the transmit buffer when TSC=1, 0.5 to 1.5 cycles of the data shift cycle is necessary until changing to TSC=0.
signal
signal
source selection bit (TIC) of the serial I/O control register.
X
X
D
D
TBE=0
TSC=0
TBE=1
ST
ST
D
D
0
0
TBE=0
D
D
1
1
5
1 start bit
7 or 8 data bit
1 or 0 parity bit
1 or 2 stop bit (s)
/T
X
D pin.
16
16
16
spectively). Writing “0” to the serial I/O enable bit SIOE (bit 7 of
the Serial I/O Control Register) also clears all the status flags, in-
cluding the error flags.
All bits of the serial I/O1 status register are initialized to “0” at re-
set, but if the transmit enable bit (bit 4) of the serial I/O control reg-
ister has been set to “1”, the transmit shift completion flag (bit 2)
and the transmit buffer empty flag (bit 0) become “1”.
Transmit buffer/Receive buffer register (TB/
RB) 0018
The transmit buffer and the receive buffer are located at the same
address. The transmit buffer is write-only and the receive buffer is
read-only. If a character bit length is 7 bits, the MSB of data stored
in the receive buffer is “0”.
Baud rate generator (BRG) 001C
The baud rate generator determines the baud rate for serial trans-
fer.
The baud rate generator divides the frequency of the count source
by 1/(n + 1), where n is the value written to the baud rate genera-
tor.
RBF=1
SP
SP
TBE=1
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
ST
ST
16
D
0
D
0
RBF=0
D
D
1
1
Generated at 2nd bit in 2-stop-bit mode
3806 Group
16
SP
TSC=1
RBF=1
SP
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