41CL User Manual
© 2019, Systemyde International Corporation
34
YBUILD
(starting address and transfer length in ALPHA register)
Executing
YBUILD
(
Write To Extra Functions Buffer
) copies a block of data (up to 4096
words) from memory to the
Extra Functions Buffer Area
, starting at the location
addressed by the
Extra Functions Buffer Pointer
. The Buffer Pointer is updated to point
at the next
Buffer Area
location at the end of the transfer.
When executed from the keyboard a
COPYING
message is written to the display during
the actual transfers. The transfers are executed in 50x Turbo mode, and then the current
Turbo mode is restored.
Care must be exercised because this function will wrap around the end of the Buffer
Area, back to the beginning of the
Buffer Area
, if the transfer length specified so
indicates.
The
YBUILD
function only supports physical addresses. This means that if you want to
transfer data from a physical module to the
Buffer Area
the data must first be transferred
to RAM memory so that a physical address can be specified.
The figure below shows the formatting required for the address and data for the
YBUILD
function. The transfer length
D2
-
D0
is limited to 4096 words or less, and the number
of words transferred is the transfer length.
000
indicates a transfer length of 4096 words.
ALPHA register
11
10
9
8
7
6
5
4
3
2
1
physical address
P5 P4 P3 P2 P1 P0
-
0
D2 D1 D0
Flash Memory Functions
If you are not absolutely sure of what you are doing, do not attempt to use these
functions!
While these functions do prevent you from corrupting the Operating System
of the calculator, they still allow you to erase or modify the rest of the Flash memory.
You must be familiar with how Flash memory operates before attempting to use these
functions.
Flash memory has limited endurance, typically 100,000 write cycles, and is erased by sec-
tors, which are 64K bytes (32K words, or eight pages) in the case of the 41CL. An erased
Fl
a
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0xFFFF
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Onl
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tion in Flash, which means that writes to Flash can
onl
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“
1”
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“
0”
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nd
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ve
r
vice-versa.
