SM8521 Datasheet, PDF (25/56 Pages) Sharp Electrionic Components – 8-Bit Single-Chip Microcomputer

PS1 (Interrupt enable bit (I) of processor status 1)
The bit I (bit 0 : PS1) enables/disables all maskable
interrupts. After hardware reset, the bit I is set ‘0’
and so all maskable interrupts are in disable state.
Bit 0 : Interrupt enable (I)
BIT
CONTENT
0 Disables to accept all maskable interrupts
Enables to accept maskable interrupt. For
each maskable interrupt can be enabled/
1
disabled by interrupt enable register IE0, IE1
and bits IM2-IM0.
Except that write to processor status PS1 directly,
the bit I can be set/cleared by the following special-
purpose instructions. (Under normal case, the
special-purpose instructions are used.)
DI instruction : bit I is set ‘0’.
EI instruction : bit I is set ‘1’.
IE0 (Interrupt enable register 0)
The interrupt enable register IE0 is an 8-bit
readable/writable register containing the settings for
enable/disable to accept interrupt sources.
Bit 7
DMA TIM0 - EXTINT UART -
0
- LCDC
Bit 7 : DMA interrupt enable bit
Bit 6 : Timer 0 interrupt enable bit
Bit 5 : Sets ‘0’.
Bit 4 : External interrupt enable bit
Bit 3 : UART interrupt enable bit
Bits 2 to 1 : Set ‘0’.
Bit 0 : LCD cotroller interrupt enable bit
BIT
CONTENT
0 Disable
1 Enable
SM8521
IE1 (Interrupt enable register 1)
The interrupt enable register IE1 is an 8-bit
readable/writable register containing the settings for
enable/disable to accept interrupt sources.
Bit 7
0
- TIM1 - CLK - PIO - -
Bit 7 : Sets ‘0’.
Bit 6 : Timer 1 interrupt enable bit
Bit 5 : Sets ‘0’.
Bit 4 : Clock interrupt enable bit
Bit 3 : Sets ‘0’.
Bit 2 : PIO interrupt enable bit
Bits 1 to 0 : Set ‘0’.
BIT
CONTENT
0 Disable
1 Enable
The interrupt enable register IE0 and IE1 are also
used to wake up the chip from standby mode
(STOP mode, HALT mode) by setting the interrupt
to enable. If the interrupt enabled by the interrupt
enable register IE0 and IE1 occurs, the chip will
wake up from standby mode. But also there are
interrupt sources which cannot use to wake up
from STOP mode. For more details, refer to "Stand
by Function".
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