Abov MC96FM204, User Manual

Page: 72 / 172

MC96FM204/FM214
72 April 7, 2016 Ver. 1.8
10.11 Interrupt Timing
Figure 10.10 Timing Chart of Interrupt Acceptance and Interrupt Return Instruction
Interrupt sources are sampled at the last cycle of a command. If an interrupt source is detected the lower 8-bit of
interrupt vector (INT_VEC) is decided. M8051W core makes interrupt acknowledge at the first cycle of a
command, and executes long call to jump to interrupt service routine.
NOTE) command cycle CLPx: L=Last cycle, 1=1
st
cycle or 1
st
phase, 2=2
nd
cycle or 2
nd
phase
10.12 Interrupt Register Overview
10.12.1 Interrupt Enable Register (IE, IE1, IE2, IE3)
Interrupt enable register consists of global interrupt control bit (EA) and peripheral interrupt control bits. Total 24
peripherals are able to control interrupt.
10.12.2 Interrupt Priority Register (IP, IP1)
The 24 interrupts are divided into 6 groups which have each 4 interrupt sources. A group can be assigned 4
levels interrupt priority using interrupt priority register. Level 3 is the highest priority, while level 0 is the lowest
priority. After a reset IP and IP1 are cleared to
‘00H’. If interrupts have the same priority level, lower number
interrupt is served first.
.
CLP2 CLP1 C2P1 C1P1 C2P2 C1P2 CLP2
Interrupt sampled here
8-Bit interrupt Vector
INT_SRC
INTR_ACK
LAST_CYC
INTR_LCALL
INT_VEC
PROGA
SCLK
{8
’h00, INT_VEC}