ATF1504BE ATMEL Corporation, ATF1504BE Datasheet - Page 12

• Manufacturer Part Number: ATF1504BE
• Description: High Speed CPLD
• Manufacturer: ATMEL Corporation

5.3
5.4
12
Direct Reconfiguration Access – DRA
ISP Programming Protection
ATF1504BE
Figure 5-2.
This reconfiguration mode allows the user to directly modify the internal static registers of the
CPLD without affecting the configuration data stored in the embedded memory. It is more useful
in cases where immediate and temporary context change in the function of the hardware is
desired.
The CPLD embedded configuration memory does not change when a new set of configuration
data is passed to the chip using the DRA mode. Instead, the internal static registers of the CPLD
are directly written with the data entering the chip via the JTAG port. In other words, it's a tempo-
rary change in the function performed by the CPLD since a power sequence results in the device
being configured again by the data stored in the embedded memory.
The ATF1504BE has a special feature that locks the device and prevents the inputs and I/O
from driving if the programming process is interrupted for any reason. The inputs and I/O default
to high-Z state during such a condition.
All ATF1504BE devices are initially shipped in the erased state, thereby making them ready to
use for ISP.
Note:
For more information refer to the “Designing for In-System Programmability with Atmel CPLDs”
application note.
CPLD Device
ATF1504BE
Configuration of ATF1504BE Device Using a Processor and Memory
TDO
TMS
TCK
TDI
Serial Data
Data
Processor
Memory
3637A–PLD–11/06
Address