Real Time Devices DM6804 PWM Capture

DM6804 PWM Capture block (not recommended)


Simulink® Real-Time™ Library of Drivers No Longer Recommended for Use


This block programs the AMD9513A for capturing PWM signals by using two counters. One counter measures the cycle duration, and the other counter measures the duration the signal is high.

There are two outputs. One output is the relative frequency compared to the base frequency. The other output is the duty cycle. To get the actual frequency, multiply the base frequency by the relative frequency.

The PWM signal has to enter the pins named GATE of both corresponding counter channels (parallel wiring). Both CLK pins have to be left unconnected.

Scaling Input to Output

Hardware Output

Block Input Data Type




0 to 1

Block Parameters


From the list, choose 1&2, 2&3, 3&4, 4&5. This selects which two counters the driver block uses to determine the PWM. One block is required for each counter used.

Frequency base

From the list, choose F1=5MHz, F2=500kHz, F3=50kHz, F4=5kHz, or F5=500Hz to set the base frequency. The XTAL frequency is assumed to be 1 MHz, therefore the jumper on the DM6804 has to be in position 1 MHz not 5 MHz.

Sample time

Enter the base sample time or a multiple of the base sample time. The sample time indicates the update rate of registration on the input (Duty Cycle)

Base address

Enter the base address of the board. This entry must correspond to the DIP switch setting on the board. For example, if the DIP switch setting is 300 (hexadecimal), enter 0x300.

Was this topic helpful?