
2-15
PSD3XX Famly
Configuration 
Bits
CDATA
(Note 13)
No.
of Bits
Function
8-bit or 16-bit Data Bus Width
CDATA = 0 eight bits
CDATA = 1 sixteen bits
ADDRESS/DATA Multiplexed (separate buses)
CADDRDAT = 0, non-multiplexed
CADDRDAT = 1, multiplexed
A19 or CSI
CA19/CSI = 0, enable power-down
CA19/CSI = 1, enable A19 input to PAD
Active HIGH or Active LOW
CALE = 0, Active high 
CALE = 1, Active low 
Active high or active low
CRESET  =  0, active low reset signal
CRESET  =  1, active high reset signal
Combined or Separate Address Space 
for SRAM and EPROM
0 = Combined, 1 = Separate
Port A I/Os or A0–A7
CPAF1 = 0, Port A pin = I/O
CPAF1 = 1, Port A pin = A0 – A7
Port A AD0–AD7 (address/data multiplexed bus)
CPAF2 = 0, address or I/O on Port A (according to CPAF1)
CPAF2 = 1, address/data multiplexed on Port A (track mode)
A16–A19 address or logic inputs
CATD = 0, logic inputs
CATD = 1, address inputs
A16–A19 Transparent or Latched
CADDHLT = 0, Address latch transparent
CADDHLT = 1, Address latched (ALE dependent)
SECURITY On/Off
CSECURITY = 0, off
CSECURITY = 1, on
A0–A15 Address Inputs are transparent or
ALE-dependent in non-multiplexed modes
CLOT = 0, transparent 
CLOT = 1, ALE-dependent
Determine the polarity and control methods of read and 
write cycles. 
CEDS 
CRRWR
0 
0
RD and WR active low pulses 
0 
1
R/W status and high E pulse 
1 
1
R/W status and low DS pulse
CRRWR = 0, RD and WR active low strobes
CRRWR = 1, R/W status and E active high pulse
Port A CMOS or Open Drain Output
CPACOD = 0, CMOS output
CPACOD = 1, open-drain output
1
CADDRDAT
1
CA19/CSI
1
CALE
1
CRESET
1
COMB/SEP
1
CPAF1
8
CPAF2
1
CATD
(Note 15)
1
CADDHLT
1
CSECURITY
1
CLOT
(Note 14)
1
CRRWR
CEDS
(Note 14)
2
CRRWR
(Note 15)
1
CPACOD
8
Table 5. 
PSD3XX 
Configuration 
Bits
11,12