Boot Modes 5 And 6 (Booting With Spi Master) - Siemens ERTEC 200P-2 Manual

address of the boot ROM is mapped at address 0x0000_0000 (MEM_SWAP.SWAP =
"00", see 2.3.10.9.7) and no I-TCM has been configured (if the I-TCM is configured, this
is always shown at address 0x0000_0000 irrespective of MEM_SWAP.SWAP).
Note: The reset pin of the NOR flash must be connected to ERTEC 200P reset
There is a wait of at least 70 µs in the boot operation before the NOR flash is first ac-
cessed. This procedure is necessary as the previous history is not known and a write or
delete job previously activated could be canceled by the reset. The flash block needs this
time to switch to "Read data" status.

Boot Modes 5 and 6 (Booting with SPI Master)

2.3.1.5.3
The SPI interface of the ERTEC 200P is configured with the following parameters:
- SPI of the ERTEC 200P is the master (sets the SPI clock)
- 8 Data Bits
- Transmit/Receive with MSB first
- Idle Clock Line = 0
- Data is latched with a rising edge and output with a falling edge.
- The baud rate is programmed to a fixed 1 Mb/s
- The existing SPI module supports serial interfaces that are compatible with the
Motorola, TI and NSC serial protocols.
- SPI memory chip select is addressed with GPIO31.
The SPI boot supports two types of SPI flash storage medium. Some of the SPI devices
require the command 0xE8 for reading; others can be addressed with the read command
0x03. The subsequent SPI boot is, however, identical for the two read commands. A read
command is structured as follows. In the standard sizes, 3 address bytes are used
(A0...A23). The system always starts with the highest address byte.
Following configuration of the SPI master, the boot code establishes which RD command
can be used to address the SPI device. In device detection, the read command 0xE8 with
the start address 0x0000 is first sent to the SPI device. If no identifier (ID_OK
found within 10 bytes, the read command 0xE8 is sent to the SPI device with start ad-
dress 0x010000... (for alternative boot block in SPI device for data retention purposes,
see 0). If no identifier (ID_OK
the device identifier is repeated with the command 0x03 (SPI-READ). If no identifier
(ID_OK 0x5A) can be read back by the SPI device within 10 bytes for this command
either (i.e. unprogrammed flash block), a watchdog is activated. When the watchdog
expires (HW reset activation), device detection is run again.
If an identifier is read for one of the two read commands (ID_OK = 0x5A), the position of
the identifier in the SPI data stream indicates how many address bytes (1, 2, 3 or 4 bytes)
Copyright © Siemens AG 2016. All rights reserved
Technical data subject to change
0x5A) is found within 10 bytes here either, the search for
38
0x5A) is
ERTEC 200P-2 Manual
Version 1.0