
iiBusModuLes:sRaMContRoLLeR(sRaMC)
ii-3-4
ePson
s1C33L17teChniCaLManuaL
ii.3.3.1Chipenablesignals
The S1C33L17 provides 25 bits of an external address bus, 16 bits of an external data bus, and eight chip-enable
pins (#CE4 to #CE11), allowing access to the 512MB address space.
Two or more areas are assigned to each chip-enable signal. Table II.3.3.1.1 shows the relationship between the chip-
enable pins and corresponding areas.
TableII.3.3.1.1RelationshipbetweenChip-EnablePinsandCorrespondingAreas
#Cepin
#CE4
#CE5
#CE6
#CE7
#CE8
#CE9
#CE10
#CE11
Corresponding
area
Areas4,14
Areas5,15,16
Areas17,18
Areas7,19
Areas8,21
Areas9,22
Areas10,13,20
Areas11,12
area
Area4
Area5
Area17+18
Area7
Area8
Area9
Area10
Area11+12
size
1MB
128MB
2MB
4MB
16MB
area
Area14
Area15+16
–
Area19
Area21
Area22
Area13
–
size
16MB
64MB
–
64MB
16MB
–
area
–
Area20
–
size
–
64MB
–
usablesizeofareaincontinuousaddressrange
The #CEx signal also becomes active when an address in any corresponding area is accessed.
Area 6 is allocated to the I/O area for S1C33L17 IP and peripheral circuits. Although area 6 is one of external
memory areas, external memory cannot be accessed.
ii.3.3.2areaConditionsettings
Bus access conditions can be set by area for each #CEx signal. Therefore, the same conditions for two or more
areas accommodated by the respective #CEx signals will be set.
This section describes the parameters to be set individually for each area and the relevant control bits.
The SRAMC control registers are initialized by an initial reset. These registers should be set up back again in
software to suit the external device configuration or specification as required.
For details of bus cycle operation, see Section II.3.6, “Bus Access Timing Chart.”
note: Thecontrolregisterandcontrolbitconfigurationsarethesameforall#CE4to#CE11areas.The
controlbitnamesbeginwithCE4toCE11toindicatetherelevantareas,whichinthedescription
belowarecommonlyrepresentedbyCExforallareas.
TableII.3.3.2.1AreaParameterSettings
setupitem
Devicetype
(#CE4–#CE11)
Devicesize
(#CE4–#CE9,#CE11)
Staticwaitcycle
(#CE4–#CE11)
#CEsetuptime
(#CE4,#CE11)
Outputdisabletime
(#CE9)
Content
BSL
A0
16bits
8bits
Insert7waitcycles
:
Insert0waitcycles
Nosetuptime
+1BCLK
7cycles
:
0cycles
Controlbitsettings
CExTYPE=1
CExTYPE=0(default)
CExSIZE[1:0]=01(default)
CExSIZE[1:0]=10
CExWAIT[2:0]=111(default)
:
CExWAIT[2:0]=000
CExSTUP=1
CExSTUP=0(default)
CE9HOLD[2:0]=111
:
CE9HOLD[2:0]=000(default)
endianmode
The S1C33L17 supports little endian mode only.
devicetype
The SRAMC incorporates an SRAM-type bus interface, allowing A0 (default) or BSL to be selected as the
device type. To use a BSL-type device in the #CEx area, set CExTYPE (Dx - 4/0x30150C) to 1.
CextYPe:#CExDeviceTypeSelectBitintheDeviceTypeSetupRegister(Dx-4/0x30150C)
Table II.3.3.2.2 lists the bus control signal pins used in each device type.