ST7FLITE20 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7FLITE20
STMicroelectronics
'ST7FLITE20' PDF : 133 Pages View PDF
ST7LITE2
INTERRUPTS (Cont’d)
EXTERNAL INTERRUPT CONTROL REGISTER
(EICR)
Read / Write
Reset Value: 0000 0000 (00h)
7
0
IS31 IS30 IS21 IS20 IS11 IS10 IS01 IS00
EXTERNAL INTERRUPT SELECTION REGIS-
TER (EISR)
Read / Write
Reset Value: 0000 1100 (0Ch)
7
0
ei31 ei30 ei21 ei20 ei11 ei10 ei01 ei00
Bit 7:6 = IS3[1:0] ei3 sensitivity
These bits define the interrupt sensitivity for ei3
(Port B0) according to Table 6.
Bit 5:4 = IS2[1:0] ei2 sensitivity
These bits define the interrupt sensitivity for ei2
(Port B3) according to Table 6.
Bit 3:2 = IS1[1:0] ei1 sensitivity
These bits define the interrupt sensitivity for ei1
(Port A7) according to Table 6.
Bit 1:0 = IS0[1:0] ei0 sensitivity
These bits define the interrupt sensitivity for ei0
(Port A0) according to Table 6.
Notes:
1.These 8 bits can be written only when the I bit in
the CC register is set.
2. Changing the sensitivity of a particular external
interrupt clears this pending interrupt. This can be
used to clear unwanted pending interrupts. Refer
to section “External Interrupt Function” on
page 46.
Table 6. Interrupt Sensitivity Bits
ISx1 ISx0
00
01
10
11
.
External Interrupt Sensitivity
Falling edge & low level
Rising edge only
Falling edge only
Rising and falling edge
Bit 7:6 = ei3[1:0] ei3 pin selection
These bits are written by software. They select the
Port B I/O pin used for the ei3 external interrupt ac-
cording to the table below.
External Interrupt I/O pin selection
ei31
ei30
0
0
0
1
1
0
I/O Pin
PB0 1)
PB1
PB2
Note:
1. Reset State
Bits 5:4 = ei2[1:0] ei2 pin selection
These bits are written by software. They select the
Port B I/O pin used for the ei2 external interrupt ac-
cording to the table below.
External Interrupt I/O pin selection
ei21
ei20
0
0
0
1
1
0
1
1
I/O Pin
PB3 1)
PB4 2)
PB5
PB6
Notes:
1. Reset State
2. PB4 cannot be used as an external interrupt in
HALT mode.
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