Explanation Of Operation Of Dtp/External Interrupt - Fujitsu MB90895 Series Hardware Manual

CHAPTER 12 DTP/external interrupt
12.4

Explanation of Operation of DTP/External Interrupt

The DTP/external interrupt circuit has an external interrupt function and a DTP
function.The setting and operation of each function is explained.
I Setting of DTP/External Interrupt Circuit
Using the DTP/external interrupt requires, the setting shown in Figure 12.4-1.
ICR interrupt
control register
External interrupt
EIRR/ENIR
ELVR
DDR port direction
register
: Unused bit
: Used bit
; Setting "1" to corresponding bit to used pin
0 : Setting "0"
1 : Setting "1"
G
Setting procedure
To use the DTP/external interrupt, set each register by using the following procedure:
1. Set the interrupt request enable bit corresponding to the DTP/external interrupt channel to be used to "0"
(ENIR: EN).
2. Use the detection condition select bit corresponding to the DTP/external interrupt pin or RX pin to be
used to set the edge or level to be detected.
3. Set the interrupt request flag bit corresponding to the DTP/external interrupt channel to be used to "0"
(EIRR: ER).
4. Set the interrupt request enable bit corresponding to the DTP/external interrupt channel to be used to "1"
(ENIR: EN).
• When setting the registers for the DTP/external interrupt, the external interrupt request must be disabled
in advance (ENIR: EN0 = 0).
• When enabling the DTP/external interrupt request (ENIR: EN = 1), the corresponding DTP/external
interrupt request flag bit must be cleared in advance (EIRR: ER = 0).These actions prevent the mistaken
interrupt request from occurring when setting the register.
338
Figure 12.4-1 Setting of DTP/External Interrupt Circuit
bit15 14 13 12
ICS3 ICS2 ICS1 ICS0 ISE
DTP
ER7 ER6 ER5 ER4
LB7 LA7 LB6 LA6 LB5 LA5
DTP/Setting "0" to corresponding bit to used pin as external
interrupt input
11 10 9 bit8 bit7 6
IL2 IL1 IL0 ICS3 ICS2 ICS1
0
1
ER0 EN7 EN6 EN5
Re- Re-
LB4 LA4
served served
0 0
5 4 3 2 1 bit0
ICS0 ISE IL2 IL1 IL0
0
1
Re- Re- Re-
EN4 EN0
served served served
0 0 0
Re- Re- Re- Re-
LB0 LA0
served served served served
0 0 0 0