MEC1404 Datasheet, PDF (523/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

43.18 Serial Port (UART) Timing
43.18.1 SERIAL PORT (UART) DATA TIMING
FIGURE 43-21: SERIAL PORT DATA
Data
TXD1, 2
Start
t1
Data (5-8 Bits)
MEC140X/1X
Parity ^{Stop (1-2 Bits)}
TABLE 43-22: SERIAL PORT DATA PARAMETERS
Name
t1
Description
Serial Port Data Bit Time
MIN TYP
t_BR
(Note
43-15)
MAX
Units
nsec
Note 43-15
tBR is 1/Baud Rate. The Baud Rate is programmed through the Baud_Rate_Divisor bits located in
the Programmable Baud Rate Generator registers. The selectable baud rates are listed in Table 17-
2, "UART Baud Rates using Clock Source 1.8432MHz_Clk" and Table 17-3, "UART Baud Rates using
Clock Source 24MHz_Clk". Some of the baud rates have some percentage of error because the clock
does not divide evenly. This error can be determined from the values in these baud rate tables.
43.18.2 UART_CLK TIMING
FIGURE 43-22: UART_CLK EXTERNAL CLOCK TIMING
t_R
t_H
t_F
t_L
t_P
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