19
The 3377 has four separate operating modes. The mode is determined
by the Xilinx program loaded from the eprom, see below for changing
operating mode. The times are measured with respect to a common hit,
which can occur before or after the individual time signal to be measured
(Common Stop or Common Start mode). The other mode dependent
feature is the data format, which can be either single or double word. A
summary of the modes is listed below.
Mode
Operation
Data Format
0
Common Stop
Single Word (Default Mode)
1
Common Start
Single Word
2
Common Stop
Double Word
3
Common Start
Double Word
Since the features and control registers of the modes are quite different
in some cases, the control registers, data word formats, and operation of
the four different modes are discussed separately in the “Operating
Modes” section.
PROGRAMMING THE UNIT
FOR A DIFFERENT MODE
OF OPERATION
When initially powered on, the module configures itself for Common
Stop, Single Word mode. The module is ready for the first command
approximately 200 milliseconds after power on. The first command
received by the module must be F9 for correct operation.
To change to any other mode the following sequence of CAMAC opera-
tions to the module is required:
1.
F30, any subaddress. This selects programming mode and resets
the Xilinx gate array. The default program load is the Common Stop
mode, Single Word data format.
2.
To select a program mode other than the default, perform an F21,
F22, or F23 CAMAC operation. To reprogram the Common Stop
Single Word mode, simply skip this step.
F21, any subaddress. This selects the common start, single word
program load.
F22, any subaddress. This selects the common stop, double word
program load.
F23, any subaddress. This selects the common start, double word
program load.
3.
F25, any subaddress. This begins the programming of the Xilinx
chip, using the selected program load (or the default load). This will
take less than 200 milliseconds to complete.
OPERATING INSTRUCTIONS