MEC1322 Datasheet, PDF (179/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
14.6 Power, Clocks and Reset
This section defines the Power, Clock, and Reset parameters of the block.
14.6.1 POWER DOMAINS
TABLE 14-2: POWER SOURCES
Name
VCC1
14.6.2 CLOCK INPUTS
Description
This Power Well is used to power the registers and logic in this block.
TABLE 14-3: CLOCK INPUTS
Name
1.8432MHz_Clk
24MHz_Clk
14.6.3 RESETS
Description
The UART requires a 1.8432 MHz ± 2% clock input for baud rate
generation.
24 MHz ± 2% clock input. This clock may be enabled to generate the
baud rate, which requires a 1.8432 MHz ± 2% clock input.
TABLE 14-4: RESET SIGNALS
Name
VCC1_RESET
nSIO_RESET
RESET
Description
This reset is asserted when VCC1 is applied.
This is an alternate reset condition, typically asserted when the main
power rail is asserted.
This reset is determined by the POWER bit signal. When the power bit
signal is 1, this signal is equal to nSIO_RESET. When the power bit
signal is 0, this signal is equal to VCC1_RESET.
14.7 Interrupts
This section defines the Interrupt Sources generated from this block.
TABLE 14-5:
SYSTEM INTERRUPTS
Source
Description
UART
The UART interrupt event output indicates if an interrupt is pending. See
Table 14-13, “Interrupt Control Table,” on page 186.
TABLE 14-6:
EC INTERRUPTS
Source
UART
Description
The UART interrupt event output indicates if an interrupt is pending. See
Table 14-13, “Interrupt Control Table,” on page 186.
14.8 Low Power Modes
The UART may be put into a low power state by the chip’s Power, Clocks, and Reset (PCR) circuitry.
14.9 Description
The UART is compatible with the 16450, the 16450 ACE registers and the 16C550A. The UART performs serial-to-par-
allel conversions on received characters and parallel-to-serial conversions on transmit characters. Two sets of baud
rates are provided. When the 1.8432 MHz source clock is selected, standard baud rates from 50 to 115.2K are available.
When the source clock is 32.26 MHz, baud rates from 126K to 2,016K are available. The character options are program-
mable for 1 start; 1, 1.5 or 2 stop bits; even, odd, sticky or no parity; and prioritized interrupts. The UART contains a
programmable baud rate generator that is capable of dividing the input clock signal by 1 to 65535. The UART is also
 2014 - 2015 Microchip Technology Inc.
DS00001719D-page 179