SENA HD1200 - Manual (Page 40)

Starter Kit and User Manual for the HelloDevice 1200
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Figure 6.8. HelloDevice & User Device use ports of Dualport RAM
1) Dual-Port RAM Communication
To implement the hardware, refer to the specifications of the HelloDevice external interface, Dual-Port RAM
connector of Demo Board and attached data sheet of CY7C136 Dual-Port RAM. When you implement your
hardware, you can use Vcc/GND lines of Dual-Port RAM interface connector of Demo Board. This way an
additional 5V DC power supply is not required.
This section illustrates a subroutine of reading and writing each one byte in Dual-Port RAM of the HelloDevice
to help you to implement firmware of your user-defined device. This example is written in Scenix Sx
microprocessor assembly language.
Read memory
To read Dual-Port RAM, specify the address for DPROffsetLSB and DPROffsetLSB and then call
_dpramread subroutine. To read multiple bytes, call _dpramread several times.
_dpramread
mov !datalo,#$FF ; Set Data Read line as input (refer to pin 19 ~ 26)
mov addlo, DPROffsetLSB ; Set memory address (Address 0 ~ 7) : refer to 9 ~ 16
mov addhi, DPROffsetMSB ; Set memory address (Address 8 ~ 10): refer to 17 ~ 18, 33