Copyright © Siemens AG 2016. All rights reserved
247
ERTEC 200P-2 Manual
Technical data subject to change
Version 1.0
2.3.10 APB Peripherals
The function blocks connected to the APB have interfaces of differing widths. The table
below shows the access mechanisms supported and the data widths of these blocks.
Access modes
Wait states at the AHB
Bit 31:24
Bit 23:16
Bit 15:8
Bit 7:0
Read
Write
Function block
8-bit
8-bit
8-bit
8-bit
2
0
IO filter,
Boot_ROM
16-bit
16-bit
32-bit
8-bit
8-bit
8-bit
8-bit
Ready
0
PER_IF (except
PER_IF-GPIO)
16-bit
16-bit
32-bit
32-bit
2
0
GPIO,
PER_IF-GPIO,
timer0-5,
F-counter,
watchdog,
SCRB,
SPI1/2,
flash controller,
UART1-4,
I
2
C,
Host interface
Table 17:
Data width of peripherals
Access modes that are not permitted (e.g. writing byte by byte / halfword by halfword to
the timer) are not prevented by the hardware, nor are they indicated at the AHB in the
form of an error response or QVZ interrupt.
Access to memory ranges that are not decoded (marked as "not used" in memory map-
ping) triggers IRQ52 (see 2.3.2.14) and ends with a ready signal generated by the APB
address decoder. Write access does not have any effect on the system. Read access
returns undefined data.