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System Integration Module
2-16
MC68328 DRAGONBALL PROCESSOR USER’S MANUAL
MOTOROLA
2.3.2.7 INTERRUPT-PENDING REGISTER (IPR).
This read-only register indicates which
interrupts are pending. If an interrupt source requests an interrupt but that interrupt is
masked by the interrupt-mask register, that interrupt bit will be set in the interrupt-pending
register, but not in the interrupt-status register. If it is not masked, the interrupt bit will be the
same in both registers.
2.4 KEYBOARD INTERRUPT I/O
Keyboard-interrupt features provide smart power management. The MC68EC000 can be
placed in sleep mode when no keys are pressed. When a key is pressed, the MC68EC000
can wake up and serve the user’s request. This event-driven approach significantly reduces
power consumption. KB0 to KB7 are input pins for the keyboard interface. A logical OR oper-
ation is performed on these inputs to generate an interrupt, indicating to the MC68EC000
core that a key was pressed.
2.5 CHIP-SELECT REGISTERS
The following paragraphs describe the registers in the chip-select function and an example
of how to program the registers. The chip-select function does not operate until the register
is initialized and the valid bit is set in the corresponding group-base address registers. The
only exception is the CSA0, which is the boot device chip-select.
2.5.1 Group-Base Address Registers (GBR0-GBR3)
There are four 16-bit group-base address registers in the chip-select function (one for each
chip-select group). The group registers (group-base address register and group-base
address mask register) decode the upper address bits and the chip-select option registers
decode the lower address bits. There are 4 chip-selects in each group. For example, in
group A, the chip-selects are CSA0, CSA1, CSA2, and CSA3.
GROUP BASE ADDRESS (GBA31-GBA20)
The group-base address field (the upper 12 bits of each base address register) selects
the starting address for the group address range. The corresponding bits GBA31–GBA20
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
UNUSED
IRQ7
TMR1
SPIS
PEN
IRQ6
IRQ3
IRQ2
IRQ1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
PWM
KB
LCDC
RTC
WDT
UART
TMR2
SPIM
Address: $(FF)FFF310
Reset Value: none
Figure 2-8. Interrupt-Pending Register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
GROUP BASE ADDRESS (GBA31-GBA20)
UNUSED
V
GBA31
GBA30
GBA29
GBA28
GBA27
GBA26
GBA25
GBA24
GBA23
GBA22
GBA21
GBA20
0
0
0
0
Address: $(FF)FFF100, 102, 104, 106
Reset Value: $0000
Figure 2-9. Group-Base Address Registers
Summary of Contents for DragonBall MC68328
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Page 25: ...Overview 1 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 45: ...System Integration Module 2 20 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 103: ...Parallel Ports 7 16 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 117: ...UART 8 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 127: ...SPI Master 10 6 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...