EM6517 ETC, EM6517 Datasheet - Page 15

• Manufacturer Part Number: EM6517
• Description: 4 BIT MICROCONTROLLER
• Manufacturer: ETC

7.2.2 Pull-up or Pull-down
Each of the input port terminals PA[3:0] has a resistor integrated which can be used either as pull-up or pull-
down resistor, depending on the selected metal mask options. See the port A metal mask chapter for details.
The pull resistor can be inhibited using the NoPullPA[n] bits in the register OptNoPullPA.
Table 7.2.1. Pull-up or Pull-down Resistor on Port A Inputs
* only pull-up or pull-down may be chosen on any port A terminal (one choice is excluding the other)
7.2.3 Software Test Variables
The port A terminals PA[2:0] are also used as input conditions for conditional software branches. Independent
of the OPTDebIntPA and the OPTIntEdgPA. These CPU inputs always have a debouncer.
- Debounced PA[0] is connected to CPU TestVar1.
- Debounced PA[1] is connected to CPU TestVar2.
- SWB signal SWBEmpty is connected to CPU TestVar3
7.2.4 Port A for 10-Bit Counter
The PA[0] and PA[3] inputs can be used as the clock input terminal for the 10 bit counter in "event count" mode.
As for the IRQ generation one can choose debouncer or direct input with the register OPTDebIntPA and non-
inverted or inverted input with the register OPTIntEdgPA. Debouncer input is always recommended.
7.3 Port A registers
Table 7.3.1 Register RegPA
Table 7.3.2 Register RegIRQMask1
Option mask
MPAPU[n]
pull-up
*Direct read on port A terminal
Default "0" is: interrupt request masked, no new request stored
yes
yes
yes
no
no
no
Bit
Bit
3
2
1
0
3
2
1
0
MaskIRQPA[3]
MaskIRQPA[2]
MaskIRQPA[1]
MaskIRQPA[0]
PAData[3]
PAData[2]
PAData[1]
PAData[0]
Name
Name
Option mask
MPAPD[n]
pull-down
FOR ENGINEERING ONLY
yes
yes
yes
no
no
no
Reset
Reset
0
0
0
0
-
-
-
-
NoPullPA[n]
value
0
1
0
1
x
x
R/W
R/W
R/W
R/W
R/W
R/W
R*
R*
R*
R*
no pull-up , no pull-down
no pull-up, no pull-down
no pull-up, no pull-down
Interrupt mask for PA[3] input
Interrupt mask for PA[2] input
Interrupt mask for PA[1] input
Interrupt mask for PA[0] input
no pull-up, pull-down
pull-up, no pull-down
not allowed*
PA[3] input status
PA[2] input status
PA[1] input status
PA[0] input status
Action
Description
Description
© EM Microelectronic-Marin SA, 09/99, Rev. A/277
EM6517
with
n=0…3
15