UPD780828A Datasheet, PDF (340/472 Pages) NEC – 8-bit Single-Chip Microcontroller

Chapter 19 Meter Controller / Driver
(5) Output control circuit
This circuit consists of a Pch and Nch drivers and can drive a meter in H bridge configuration by
connecting a coil. When a meter is driven in half bridge configuration, the unused pins can be
used as normal output port pins.
The relation of the duty factor of the PWM signal output from the SMnm pin is indicated by the
following expression (n = 1 to 4, m = 0, 1).
PWM (duty) = ^{Set value of MCMPnm × cycle of MCNT count clock}
255 × cycle of MCNT count clock
×
100%
=
Set
value
of MCMPnm
255
× 100%
Cautions: 1. MCMPn0 and MCMPn1 cannot be read or written by a 16-bit access instruction.
2. MCMPn0 and MCMPn1 are in master-slave configuration, and SMCNT is com-
pared with a slave register. The PWM pulse is not generated until the first over-
flow occurs after the counting operation has been started because the compare
data is not transferred to the slave.
(6) Meter Controller/Driver Clock Switch
The input clock of the meter controller/driver can be selected with the meter controller/driver clock
switch. By default the register is set to 00H of RESET.
SMSWI is a register that supports read/write only as 8-bit instruction.
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User’s Manual U16504EE1V1UD00