Figure 3-13. Vocoder Memory Mapping - Motorola ASTRO Digital Spectra Plus Service Manual

Theory of Operation: ASTRO Spectra VOCON Board
$FFFF
$E000
$DFFF
$A000
$9FFF
$8000
$7FFF
$2000
$1FFF
$1000
$0FFF
$0200
$01FF
$0000
The ADSIC internal registers are decoded internally and start at $E000 in Dy:. These registers are
decoded using A0-A2, A13-A15, and PS* from the DSP. The ADSIC internal registers are 16 bits
wide, so only D8-D23 are used.
6881076C25-D
P Dx
ADS Vectors
External ROM External ROM
16KB Physical 16KB Physical
Banks
Banks
$00000-1FFFF $20000-3FFFF
Not Used
External
External
RAM RAM
U401 U402
ADS P Ram
ADS Dx Ram
Internal X Rom
Internal P Ram
Internal Dx Ram

Figure 3-13. Vocoder Memory Mapping

Dy
ADSIC
Registers
External
RAM
U403
ADS Dy Ram
Internal Y Rom
Internal Dy Ram
MAEPF-26007-A
3-27
October 28, 2002