Ocean Optics PC2000-PC_104 - Manual (Page 11)

PC2000-PC/104 Data Sheet
Counters
The PC2000-PC104 implemented the core of an 82C54 programmable timer in the FPGA to
implement the required clock signals. Refer to this data sheet for more detailed information. This
implementation requires no control word to be written to the counter. These timers use the equivalent
of control mode 3 (50% duty cycle) and the counters are always enabled. The base frequency for each
of the timers is shown in Table 1.
Programming
Pseudo-code programming for the PC2000-PC104 is provided in PC2000-PC/104 Programming
Sequence .
PC2000-PC/104 Programming Sequence
This technical document describes the programming procedures necessary to control and PC2000-
PC104 spectrometer. This setup is functionally identical to the S2000 spectrometer and ADC1000 ISA
card. The pseudo-code examples below use the following definitions:
(Note: all numbers starting with "0x" are in hexidecimal.)
• source code is in this font
comments are in this font
• outport_byte(baseadd+1,0x13) -- outputs one byte of data to the specified port,
represented as an offset from the base address
• outport_word(baseadd+1,0xffff) -- outputs one word of data to the specified port,
represented as an offset from the base address
• inport_byte(baseadd+3) -- inputs one byte of data from the specified port,
represented as an offset from the base address
• inport_word(baseadd+5) -- inputs two bytes (one 16-bit word) of data from the
specified port, represented as an offset from the base address
• Variables:
baseadd -- the base address in decimal, 16-bit integer
dsf -- digital sample frequency, or A/D conversion frequency, 16-bit integer
fdc -- number of flashes per scan, 16-bit integer
cmd -- command to be sent to A/D card, 8-bit (unsigned) integer
average -- number of scans to average
oldvect -- stored interrupt vector
current_channel -- active spectrometer channel
indata -- data read from the A/D card
irq -- the interrupt number (interrupt request) of the ADC500/ADC1000/PC1000
ihandler -- the interrupt handler function
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