Specifications

Flash Program Memory
13-8
13.4 Flash Program Memory
The Flash module is generally used to provide permanent program storage.
The Flash can emulate standard EEPROM or can be programmed and electri-
cally erased many times to allow code development. The ’240x Flash is similar
to that on the ’24x devices, with some key differences and enhancements.
’240x Flash features are as follows:
- Flash run-time execution at 3.3 V
- Flash programming requires a 5-V supply (±5%) at V
CCP
pin
- Flash has multiple sectors that can be protected while erasing
- Flash programming registers are similar to those on the ’24x devices
- Flash programming is done through CPU
- ’240x devices comes with JTAG interface to aid programming and emula-
tion
- A 256-word Boot ROM is available on ’240x devices to enable program-
ming through SCI or SPI ports.
The following sections explain the Flash programming registers and their bit
functions. Flash programming utilities will be provided by Texas Instruments
(TI). Refer to the TI’s web page (www.ti.com, under ’24x Flash tools) for revi-
sions of these utilities.
13.4.1 Flash Control Mode Register (FCMR)
The Flash control mode register is in internal I/O space FF0Fh. This register
is a dummy register address to enable the Flash in Flash array mode or in
Flash control register mode.
The Flash control registers are used to program the Flash array. These regis-
ters are a part of the Flash wrapper and are mapped at the same start address
as the Flash array itself. These registers are not visible (disabled) during Flash
array mode (i.e., Flash read). During the Flash control register mode, the Flash
program control registers are enabled and the Flash array is disabled (i.e., not
accessible to CPU). To enter and exit the Flash control register mode, the in-
structions in Table 13–5 are used.