Intel 8XC196MH User Manual
9-15
WAVEFORM GENERATOR
9.4.2
Controlling the Protection Circuitry and EXTINT Interrupt Generation
The protection register (Figure 9-9) controls the protection circuitry and EXTINT interrupt re-
quests.
quests.
WG_PROTECT
Address:
Reset State (MC, MD)
Reset State (MH):
1FCEH
F0H
E0H
The waveform protection (WG_PROTECT) register enables and disables the outputs and the
protection circuitry. It also selects either level-sensitive or edge-triggered EXTINT interrupts, and
selects which level or edge will generate an EXTINT interrupt request.
protection circuitry. It also selects either level-sensitive or edge-triggered EXTINT interrupts, and
selects which level or edge will generate an EXTINT interrupt request.
7
0
8XC196MC, MD
—
—
—
—
ES
IT
DP
EO
7
0
8XC196MH
—
—
—
PT
ES
IT
DP
EO
Bit
Number
Bit
Mnemonic
Function
7:5
—
Reserved; for compatibility with future devices, write zeros to these bits.
6†
PT
Protection Type
This bit selects the method used for disabling the outputs.
0 = inactive states
1 = weak pull-ups
1 = weak pull-ups
3:2
ES
IT
IT
Enable Sampling and Interrupt Type
The ES bit selects whether the protection circuitry samples the EXTINT
signal level or detects a signal transition (edge), while the IT bit controls
which value of the edge or level triggers an interrupt request. The
possible combinations are as follows.
signal level or detects a signal transition (edge), while the IT bit controls
which value of the edge or level triggers an interrupt request. The
possible combinations are as follows.
ES
IT
Event
0
0
falling edge
0
1
rising edge
1
0
low level
1
1
high level
1
DP
Disable Protection
This bit enables and disables the protection circuitry.
0 = enable protection
1 = disable protection
1 = disable protection
0
EO
Enable Outputs
This bit enables and disables the outputs.
0 = disable outputs
1 = enable outputs
1 = enable outputs
†
On the 8XC196MC, MD devices, this bit is reserved. For compatibility with future devices, always
write as zero.
write as zero.
Figure 9-9. Waveform Generator Protection (WG_PROTECT) Register