Microprocessor Programming of Actel’s Low-Power Flash Devices
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Programming Algorithm
JTAG Interface
The low-power flash families are fully compliant with the IEEE 1149.1 (JTAG) standard. They
support all the mandatory boundary scan instructions (EXTEST, SAMPLE/PRELOAD, and BYPASS) as
well as six optional public instructions (USERCODE, IDCODE, HIGHZ, and CLAMP).
IEEE 1532
The low-power flash families are also fully compliant with the IEEE 1532 programming standard.
The IEEE 1532 standard adds programming instructions and associated data registers to devices
that comply with the IEEE 1149.1 standard (JTAG). These instructions and registers extend the
capabilities of the IEEE 1149.1 standard such that the Test Access Port (TAP) can be used for
configuration activities. The IEEE 1532 standard greatly simplifies the programming algorithm,
reducing the amount of time needed to implement microprocessor ISP.
Implementation Overview
To implement device programming with a microprocessor, the user should first download the C-
based STAPL player or DirectC code from the
Actel website. (See the Actel website for future
updates regarding the STAPL player and DirectC code). Using the easy-to-follow Actel user's guide,
create the low-level application programming interface (API) to provide the necessary basic
functions. These API functions act as the interface between the programming software and the
The API is then linked with the STAPL player or DirectC and compiled using the microprocessor's
compiler. Once the entire code is compiled, the user must download the resulting binary into the
MCU system's program memory (such as ROM, EEPROM, or flash). The system is now ready for
programming.
To program a design into the FPGA, the user creates a bitstream or STAPL file using the Actel
Designer software, downloads it into the MCU system's volatile memory, and activates the stored
bitstream or STAPL file can be removed from the system, as the configuration profile is stored in
the flash FPGA fabric and does not need to be reloaded at every system power-on.
Figure 17-2 Device Programming Code Relationship
STAPL File
STAPL Player or DirectC
API
Programming
algorithm and data
Programming
software
I/O and memory
functions