XE8805 SEMTECH [Semtech Corporation], XE8805 Datasheet - Page 56

• Manufacturer Part Number: XE8805
• Description: Data Acquisition MCU
• Manufacturer: SEMTECH [Semtech Corporation]

9.1 Features
The XE8000 chips support 8 event sources, divided into 2 levels of priority.
9.2 Overview
A CPU event is generated and memorized when an event source becomes active. The 8 event sources are divided
into 2 levels of priority: High (4 event sources) and Low (4 event sources). Those 2 levels of priority are directly
mapped to those supported by the CoolRisc (EV0 and EV1; see CoolRisc documentation for more information).
RegEvn is an 8-bit register containing flags for the event sources. Those flags are set when the event is enabled
(i.e. if the corresponding bit in the registers RegEvnEn is set) and a rising edge is detected on the corresponding
event source.
Once memorized, writing a ‘1’ in the corresponding bit of RegEvn clears an event flag. Writing a ‘0’ does not
modify the flag. All interrupts are automatically cleared after a reset.
Two registers are provided to facilitate the writing of event service software. RegEvnPriority contains the number
of the highest priority event set (its value is 0xFF when no event is set). RegEvnEvn indicates the priority level of
the current interrupts. RegEvnEvn and RegEvnPriority ‘s values are dependent upon the memorized state of the
events (as reflected in flags in RegEvn).
9.3 Register map
© Semtech 2006
7
6
5
4
3
2
1
0
pos.
RegEvn[7]
RegEvn[6]
RegEvn[5]
RegEvn[4]
RegEvn[3]
RegEvn[2]
RegEvn[1]
RegEvn[0]
RegEvn
r
c1
r
c1
r
c1
r
c1
r
c1
r
c1
r
c1
r
c1
rw
Table 9-1: RegEvn
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
reset
9-2
event #7 (high priority)
clear event #7 when written 1
event #6 (high priority)
clear event #6 when written 1
event #5 (high priority)
clear event #5 when written 1
event #4 (high priority)
clear event #4 when written 1
event #3 (low priority)
clear event #3 when written 1
event #2 (low priority)
clear event #2 when written 1
event #1 (low priority)
clear event #1 when written 1
event #0 (low priority)
clear event #0 when written 1
function
XE8805/05A
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