SPC251A Sunplus Technology Co., Ltd., SPC251A Datasheet - Page 5

• Manufacturer Part Number: SPC251A
• Description: 256KB SOUND CONTROLLER
• Manufacturer: Sunplus Technology Co., Ltd.

6. FUNCTIONAL DESCRIPTIONS
6.1. CPU
The 8-bit microprocessor of SPC251A is a high performance
processor equipped with Accumulator, Program Counter, X
Register, Stack pointer and Processor Status Register (this is the
same as the 6502 instruction structure).
perform with 6.0MHz (max.) depending on the application
specifications.
6.2. Oscillator
The SPC251A supports AT-cut parallel resonant oscillated Crystal
/ Resonator or RC Oscillator or external clock sources by mask
option (select one from those three types).
application circuit should follow the vendors’ specifications or
recommendations.
X’TAL/ROSC circuits for most applications:
6.3. Mask Option
The SPC251A has the following mask option:
6.4. ROM Area
The SPC251A provides a 256K-byte ROM that can be defined as
the program area, audio data area, or both. To access ROM,
users should program the BANK SELECT Register, choose bank,
and access address to fetch data.
6.5. RAM Area
The SPC251A total RAM consists of 128 bytes (including Stack) at
locations from $80 through $FF.
6.6. Volume Control Function
The SPC251A contains a volume control function that provides an
8-step volume controller to control current D/A output. A volume
control function selector (Enable/Disable) register and controller
register is provided.
© Sunplus Technology Co., Ltd.
Proprietary & Confidential
hSupports Crystal Resonator or Rosc (with mask option).
(a) Crystal or
XI/R
20 pf
Connections
Ceramic Resonator
SPC251A
XO
The diagrams listed below are typical
20 pf
VDD
Rosc
(b) RC Oscillator
XI/R
Connections
SPC251A
SPC251A is able to
The design of
XO
5
*I/O PORT:
*NMI SOURCE:
*INT SOURCE:
6.8. I/O Port Configuration*
6.7. Map of Memory and I/Os
─
─
─
─
─
─
─
─
─
INTA (from TIMER A)
INTB (from TIMER B)
CPU CLK / 1024
CPU CLK / 8192
CPU CLK / 65536
EXT INT
PORT IOA
I/O CONFIG $0000
INTA (from TIMER A)
Input/Output IOB port : IOB3 - 0
Input/Output IOB port : IOB7 - 4
IOB
IOC
IOD
OD : Open Drain
OD : Open Drain
input data
input data
$0003
$0002
$0004
$0005
$0001
logic_1
logic_2
control
control
output
output
data
data
$3FFFF
$00600
$18000
$20000
$38000
*MEMORY MAP (From ROM view)
$00000
$00080
$00100
$00200
$10000
$1FFF
$08000
OD-NMOS
OD-NMOS
or buffer
or buffer
SUNPLUS TEST PROGRAM
USER RAM and STACK
USER'S PROGRAM &
SPC251A
HW register, I/Os
ROM BANK #0
ROM BANK #1
ROM BANK #2
ROM BANK #3
ROM BANK #4
ROM BANK #7
60K
60K
DATA AREA
UNUSED
SEP. 10, 2001
Version: 1.7