NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 1172 page image

UM10503 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.User manual Rev. 1.3 — 6 July 2012 1172 of 1269NXP Semiconductors UM10503Chapter 46: LPC43xx flash programming/ISP and IAP46.4.4 Memory map after any resetWhen a user program begins execution after reset, the interrupt vectors are set to point tothe beginning of flash memory (see Figure 6).46.4.4.1 Criterion for Valid User CodeThe reserved Cortex-M4 exception vector location 7 (offset 0x 001C in the vector table)should contain the 2’s complement of the check-sum of table entries 0 through 6. Thiscauses the checksum of the first 8 table entries to be 0. The boot loader code checksumsthe first 8 locations in sector 0 of the flash. If the result is 0, then execution control istransferred to the user code.If the signature is not valid, the auto-baud routine synchronizes with the host via serial port0. The host should send a “?” (0x3F) as a synchronization character and wait for aresponse. The host side serial port settings should be 8 data bits, 1 stop bit and no parity.The auto-baud routine measures the bit time of the received synchronization character interms of its own frequency and programs the baud rate generator of the serial port. It alsosends an ASCII string ("Synchronized") to the host. In response to this the hostshould send the same string ("Synchronized"). The auto-baud routine looks atthe received characters to verify synchronization. If synchronization is verified then"OK" string is sent to the host. The host should respond by sending“0" for backwards compatibility with existing tools. "OK" string issent to the host after receiving “0". If synchronization is not verified then theauto-baud routine waits again for a synchronization character.Once the UART has established synchronization, the boot loader invokes the ISPcommand handler. For safety reasons an "Unlock" command is required before executingthe commands resulting in flash erase/write operations and the "Go" command. The restof the commands can be executed without the unlock command. The Unlock command isrequired to be executed once per ISP session. The Unlock command is explained inSection 46.7.46.4.5 Communication protocolAll ISP commands should be sent as single ASCII strings. Strings should be terminatedwith Carriage Return (CR) and/or Line Feed (LF) control characters. Extra and characters are ignored. All ISP responses are sent as terminated ASCIIstrings. Data is sent and received in UU-encoded format.46.4.5.1 ISP command format"Command Parameter_0 Parameter_1 … Parameter_n" "Data" (Data only forWrite commands).46.4.5.2 ISP response format"Return_CodeResponse_0Response_1 …Response_n" "Data" (Data only for Read commands).46.4.5.3 ISP data formatThe data stream is in UU-encoded format. The UU-encode algorithm converts 3 B ofbinary data in to 4 B of printable ASCII character set. It is more efficient than Hex formatwhich converts 1 byte of binary data in to 2 bytes of ASCII hex. The sender should send