Micronas SDA 6000, User Manual

Page: 53 / 412

SDA 6000
PRELIMINARY DATA SHEET
Version 2.1
C16X Microcontroller
4 - 22 Micronas
Access to segments 65 to 255 selects the XBUS. This address range (41’0000
H
...
FF’FFFF
H
) is not remapped by the C16x.
b) Mapping by caches:
In normal operation mode the address requested by the controller is not altered by
ICACHE and DCACHE. In bootstrap loader mode, instruction fetches via the
ICACHE are mapped to the boot ROM by the ICACHE:
• Address is mapped to address mod 40
H
Operand reads via ICACHE and all accesses via DCACHE are passed unaltered to
the AMI.
c) Mapping and redirection in AMI:
Address mapping in AMIdepends on the settings of the ESFRs REDIR and REDIR1
as well as on the total amount of static memory. The mapping is done in the
following order:
1) Check for redirection via REDIR1: If the requested address lies in segment 255
the segment address is replaced by the low byte of REDIR1.
2) Check for redirection via REDIR: If the address resulting from step1 lies in the
address range specified by REDIR, the address is shifted to SDRAM area:
• Address is mapped to 80’0000
H
+ address – REDIR_LOWER 16 kBytes
3) If the total amount of static memeory in 4 MBytes or less (i.e. SALSEL “111”
or SALSEL = “111” and no second device present) and the address resulting from
step 2 is below 4 MBytes the address is shifted by 4 MBytes:
• Address is mapped to a 40’0000
H
This means that the address ranges 02’0000
H
... 40’FFFF
H
(PMBUS) and 41’0000
H
... 7F’FFFF
H
(XBUS) in the address space of the C16x are mapped to the same
physical memory. The overlap allows to make use of 2 independent busses for
code (PMBUS) and data (XBUS) for fast parallel access.
If the total amount of static memory is 8 MBytes (i.e. SALSEL = “111” and a second
device is present) no further mapping occurs.
d) Mapping to addresses of specific physical devices by EBI:
1) dynamic memory:
• addresses 80’0000
H
... FF’FFFF
H
(9F’FFFF
H
) access the 64MBit (16 MBit) SDRAM
(CSSDRAM)
2) static memory:
In the total amount of static memory is 4 MBytes or less (see above) the requests
of the AMI or the DG in the address range 40’0000
H
... 7F’FFFF
H
are passed to the
external static memory devices according to the SALSEL and CSENA settings (see
Chapter 6.1 ). The address range 00’0000
H
... 3F’FFFF
H
must not be used. If the
total amount of the static memory is 8 MBytes there is no reserved address range: