Chapter 14: Using Jam STAPL for ISP via an Embedded Processor
Software Development
14–11
1
Other than the
jbistub.c file,
Altera strongly recommends keeping source code in
other files unchanged from their default state. Altering the source code in these files
will result in unpredictable Jam Player operation.
Jam STAPL Byte-Code Player Memory Usage
The Jam STAPL Byte-Code Player uses memory in a predictable manner. This section
documents how to estimate both ROM and RAM memory usage.
Estimating ROM Usage
Use the following equation to estimate the maximum amount of ROM required to
store the Jam Player and JBC file:
Equation 14–1.
ROM
Size
= JBC file size + Jam player size
The JBC file size can be separated into two categories: the amount of memory required
to store the programming data, and the space required for the programming
algorithm. Use the following equation to estimate the JBC file size:
Equation 14–2.
N
JBC file size = Alg +
∑
Data
k
=1
Notes to
(1)
Alg
=Space used by algorithm.
(2)
Data
=Space used by compressed programming data.
(3)
k
=Index representing device being targeted.
(4)
N
=Number of target devices in the chain.
This equation provides a JBC file size estimate that may vary by ±10%, depending on
device utilization. When device utilization is low, JBC file sizes tend to be smaller
because the compression algorithm used to minimize file size is more likely to find
repetitive data.
The equation also indicates that the algorithm size stays constant for a device family,
but the programming data size grows slightly as more devices are targeted. For a
given device family, the increase in JBC file size (due to the data component) is linear.
shows algorithm file size constants when targeting a single MAX II device.
Table 14–2.
Algorithm File Size Constants Targeting a Single Altera Device Family
Device
MAX II
Typical JBC File Algorithm Size (Kbytes)
24.3
ALTERA [ ALTERA CORPORATION ]
