em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 108

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78F648/644/642/641/548/544/542/541N
8-Bit Microcontroller
98 •
6.6.1 UART Mode
Three UART modes are available. Mode 1 (7 bits data) and Mode 2 (8 bits data)
allow the addition of a parity bits. The parity bit addition is not available in Mode 3.
Figure below shows the data format in each mode.
6.6.2 Transmitting
In transmitting serial data, the UART operates as follows:
1. Sets the TXE bit of the URCR1 register to enable the UART transmission function.
2. Writes data into the URTD register and the UTBE bit of the URCR1 register will
3. Then start transmitting.
4. Serially transmitted data in the following order from the TX pin (see Figure 6-12b
be set by hardware.
above):
a) Start bit:
b) Transmit data: 7, 8, or 9 bits data are output from the LSB to the MSB.
c) Parity bit:
d) Stop bit:
e) Mark state:
After transmitting the Stop bit, the UART generates a TBEF interrupt (if enabled).
Figure 6-13 UART Modes 1, 2, &3 Data Formats
One “1” bit (stop bit) is output.
Output “1” continues until the start bit of the next transmitted
One “0” bit is output.
One parity bit (odd or even selectable) is output.
data.
(This specification is subject to change without further notice)
NOTE
Product Specification (V1.0) 05.05.2010