EM6603
3.3 Input port (PA0..PA3) RESET
With a mask option it is possible to choose from four PortA reset combinations. The selected ports must be
simultaneously high for at least 2ms/16ms (CLK = 32kHz) due to the presence of debouncers. Note also, that
RESET with port A is not possible during SLEEP mode.
Below are the combinations of Port A (PA0..PA3) inputs, which can be used to generate a RESET. They can be
selected by metal « PortA RESET » mask option, described in chapter 14.
Table 3. PortA Inputs RESET options (metal Hardware option)
Function
Opt. Code
Option A no inputs RESET
Option B RESET = PA0 * PA1
Option C RESET = PA0 * PA1 * PA2
RA0
RA1
RA2
Option D RESET = PA0 * PA1 * PA2 * PA3 RA3
3.4 Watchdog Timer RESET
The Watchdog Timer RESET is a software option and if used it will generate a RESET if it is not cleared. See
section 5. Watchdog timer for details.
Table 4. Watchdog-Timer Option (software option)
Watchdog Function
NoWD bit in Option register
Without Watchdog Time-out reset
1
With Watchdog Time-out reset
0
3.5 CPU State after RESET
RESET initialises the CPU as shown in the Table 5 below.
Table 5. Initial Value After RESET
name
bits
12
12
12
2
symbol
PC0
PC1
PC2
SP
initial value
$000 (as a result of Jump 0)
undefined
Program counter 0
Program counter 1
Program counter 2
stack pointer
index register
Carry flag
undefined
SP(0) selected
undefined
7
IX
1
CY
undefined
Zero flag
1
Z
undefined
HALT
1
HALT
IR
0
Instruction register
periphery registers
16
4
Jump 0
see peripheral memory map
03/02 REV. G/439
7
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Copyright 2002, EM Microelectronic-Marin SA
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