MC68HC908GT16 Datasheet, PDF (290/412 Pages) Motorola, Inc – Microcontrollers

Enhanced Serial Communications Interface (ESCI)
18.10 ESCI Arbiter
The ESCI module comprises an arbiter module designed to support
software for communication tasks as bus arbitration, baud rate recovery
and break time detection. The arbiter module consists of an 9-bit counter
with 1-bit overflow and control logic. The CPU can control operation
mode via the ESCI arbiter control register (SCIACTL).
18.10.1 ESCI Arbiter Control Register
Address: $000A
Bit 7
6
5
4
3
2
1
Bit 0
Read:
ALOST
AFIN ARUN AROVFL ARD8
AM1
AM0 ACLK
Write:
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
Figure 18-18. ESCI Arbiter Control Register (SCIACTL)
AM1 and AM0 — Arbiter Mode Select Bits
These read/write bits select the mode of the arbiter module as shown
in Table 18-12. Reset clears AM1 and AM0.
Table 18-12. ESCI Arbiter Selectable Modes
AM[1:0]
00
01
10
11
ESCI Arbiter Mode
Idle / counter reset
Bit time measurement
Bus arbitration
Reserved / do not use
Technical Data
290
ALOST — Arbitration Lost Flag
This read-only bit indicates loss of arbitration. Clear ALOST by writing
a logic 0 to AM1. Reset clears ALOST.
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
Enhanced Serial Communications Interface (ESCI) Module
MOTOROLA