TMP1942FDU Datasheet, PDF (31/106 Pages) Toshiba Semiconductor – 32bit TX System RISC

TMP1942FD
3.3.2
Single Boot Mode
In Single Boot mode, the flash memory can be re-programmed by using a program
contained in the TMP1942FD on-chip boot ROM. This boot ROM is a masked ROM. When
Single Boot mode is selected upon reset, the boot ROM is mapped to the address region
including the interrupt vector table while the flash memory is mapped to an address region
different from it (See Figure 3.2.2).
Single Boot mode allows serial programming of the flash memory. Channel 0 of the SIO
(SIO0) of the TMP1942FD is connected to an external host controller. Via this serial link, a
programming routine is downloaded from the host controller to the TMP1942FD on-chip
RAM. Then, the flash memory is re-programmed by executing the programming routine.
The host sends out both commands and programming data to re-program the flash memory.
Communications between the SIO0 and the host must follow the protocol described later.
To secure the contents of the flash memory, the validity of the application’s password is
checked before a programming routine is downloaded into the on-chip RAM. If password
matching fails, the transfer of a programming routine itself is aborted.
As in the case of User Boot mode, all interrupts including non-maskable (NMI) interrupt
must be globally disabled in Single Boot mode while the flash memory is being erased or
programmed.
Once re-programming is complete, it is recommended to protect relevant flash blocks from
accidental corruption during subsequent Single-Chip (Normal mode) operations. For a
detailed description of the erase and program sequences, refer to section 3.4. On-Board
Programming and Erasure.
Note: In Single Boot mode, the boot ROM programs are executed in Normal mode. Do not switch to any other mode in the
programming routine.
TMP1942FD-30