Figure 15-1: Block Diagram Of Asynchronous Serial Interface N - NEC V850E/PH2 User Manual

(11) UARTCn transmit data register (UCnTX)
The UCnTX register is an 8-bit transmit data buffer. Transmission starts when transmit data is
written to the UCnTX register. When data can be written to the UCnTX register (when data of one
frame is transferred from the UCnTX register to the UARTCn transmit shift register), the
transmission enable interrupt (INUCnT) is generated.

Figure 15-1: Block Diagram of Asynchronous Serial Interface n

INTUCnT
INTUCnR
INTUCnRE
shift register
f /2
XX
f /4
XX
f /8
XX
f /16
XX
f /32
XX
f /64
XX
f /128
XX
f /256
XX
f /512
XX
f /1024
XX
f /2048
XX
f /8192
XX
Remarks: 1. n = 0, 1
2. f : Internal system clock
XX
Chapter 15 Asynchronous Serial Interface C (UARTC)
Reception unit
UCnRX
Receive
Reception
controller
Filter
Baud rate
generator
Selector
UCnCTL1
UCnCTL0
UCnCTL2
User's Manual U16580EE3V1UD00
Internal bus
Transmission
unit
Transmission
controller
Baud rate
generator
UCnSTR
UCnSTR1
Internal bus
UCnTX
Transmit
shift register
Selector
UCnOTP0
UCnOTP1
TXDCn
RXDCn
611