TC1796
Peripheral Units (Vol. 2 of 2)
Analog-to-Digital Converter (ADC)
User’s Manual
25-49
V2.0, 2007-07
ADC, V2.0
25.1.10
Synchronization of Two ADC Modules
In order to synchronize conversions in two ADC modules, a synchronization logic is
implemented in the ADC module. A handshake mechanism guarantees the
synchronization between two ADCs without additional CPU load. As shown in
, two ADC modules are coupled via the synchronization bridge. Neither
Module 0 nor Module 1 has a fixed assignment as master or slave. Because each
module can request to be master, a synchronization and handshake mechanism
guarantees an appropriate master-slave coordination.
Figure 25-26 Synchronization of Two A/D-Converter
Each ADC module provides a synchronization status register SYSTAT. The conversion
request and the control information for a synchronized conversion are always driven by
the initiating ADC module, which is referred to as master. Because the master transfers
all control information necessary for the synchronized conversion in the slave, the
channel number, the A/D Converter resolution, the external multiplexer information and
the cancel-synchronize-repeat information are identical in both modules. The timing
information as well as the service request generation can be different in the two modules
(for instance, a synchronized conversion is started in both ADC modules for channel
number 5, 12-bit resolution, with identical external multiplexer information). Note that the
cancel-synchronize-repeat information is needed only in the slave module in order to
determine whether a currently running conversion will be cancelled.
The control bits of register SYSTAT retain their values if the synchronized conversion is
started except that the request bit is automatically cleared on a start of the synchronized
A/D Converter
Module 0
A/D Converter
Module 1
MCA06029
A/D
Converter
16
Analog Inputs
Synchronization
Logic
Arbiter
Synchronization
Bridge
A/D
Converter
16
Analog Inputs
Synchronization
Logic
Arbiter
Request
Acknowledge
Request
Acknowledge