NXP targets: Improved baudrate calculation function #116
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Uses 100% integer math, delivers more accurate results with fewer iterations in less time.
Since it seems most of the NXP chips use identical math, I have also altered the other targets in this commit.
If there are non-NXP chips which use a similar serial block, consider porting to those as well
Comparison:
BAUD DL MUL DIV CPU_CLOCK
------- --- --- --- ----------
new: { 9600, 625, 1, 0, 96000000}, // Actual baud: 9600, error =0.00%, 1 iterations
old: { 9600, 625, 1, 0, 96000000}, // Actual baud: 9600, error =0.00%, 0 iterations
new: { 38400, 125, 4, 1, 96000000}, // Actual baud: 38400, error =0.00%, 8 iterations
old: { 38400, 81, 14, 13, 96000000}, // Actual baud: 38409, error +0.02%, 420 iterations
new: { 57600, 81, 7, 2, 96000000}, // Actual baud: 57613, error +0.02%, 120 iterations
old: { 57600, 54, 14, 13, 96000000}, // Actual baud: 57613, error +0.02%, 315 iterations
new: { 115200, 27, 14, 13, 96000000}, // Actual baud: 115226, error +0.02%, 120 iterations
old: { 115200, 27, 14, 13, 96000000}, // Actual baud: 115226, error +0.02%, 210 iterations
new: { 230400, 23, 15, 2, 96000000}, // Actual baud: 230179, error -0.10%, 120 iterations
old: { 230400, 17, 15, 8, 96000000}, // Actual baud: 230179, error -0.10%, 525 iterations
new: { 250000, 24, 1, 0, 96000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 24, 1, 0, 96000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 6, 1, 0, 96000000}, // Actual baud: 1000000, error =0.00%, 1 iterations
old: {1000000, 6, 1, 0, 96000000}, // Actual baud: 1000000, error =0.00%, 0 iterations
new: {2000000, 3, 1, 0, 96000000}, // Actual baud: 2000000, error =0.00%, 1 iterations
old: {2000000, 3, 1, 0, 96000000}, // Actual baud: 2000000, error =0.00%, 0 iterations
new: { 9600, 514, 15, 4, 100000000}, // Actual baud: 9600, error =0.00%, 110 iterations
old: { 9600, 337, 15, 14, 100000000}, // Actual baud: 9593, error -0.07%, 1365 iterations
new: { 38400, 93, 4, 3, 100000000}, // Actual baud: 38402, error +0.01%, 120 iterations
old: { 38400, 85, 12, 11, 100000000}, // Actual baud: 38363, error -0.10%, 525 iterations
new: { 57600, 62, 4, 3, 100000000}, // Actual baud: 57604, error +0.01%, 120 iterations
old: { 57600, 61, 9, 7, 100000000}, // Actual baud: 57633, error +0.06%, 840 iterations
new: { 115200, 31, 4, 3, 100000000}, // Actual baud: 115207, error +0.01%, 120 iterations
old: { 115200, 31, 4, 3, 100000000}, // Actual baud: 115207, error +0.01%, 525 iterations
new: { 230400, 19, 7, 3, 100000000}, // Actual baud: 230263, error -0.06%, 120 iterations
old: { 230400, 19, 7, 3, 100000000}, // Actual baud: 230263, error -0.06%, 735 iterations
new: { 250000, 25, 1, 0, 100000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 25, 1, 0, 100000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 5, 4, 1, 100000000}, // Actual baud: 1000000, error =0.00%, 8 iterations
old: {1000000, 5, 4, 1, 100000000}, // Actual baud: 1000000, error =0.00%, 315 iterations
new: {2000000, 2, 9, 5, 100000000}, // Actual baud: 2008929, error +0.45%, 120 iterations
old: {2000000, 2, 9, 5, 100000000}, // Actual baud: 2008929, error +0.45%, 315 iterations
new: { 9600, 625, 4, 1, 120000000}, // Actual baud: 9600, error =0.00%, 8 iterations
old: { 9600, 404, 15, 14, 120000000}, // Actual baud: 9602, error +0.02%, 1575 iterations
new: { 38400, 179, 11, 1, 120000000}, // Actual baud: 38408, error +0.02%, 120 iterations
old: { 38400, 101, 15, 14, 120000000}, // Actual baud: 38409, error +0.02%, 525 iterations
new: { 57600, 93, 5, 2, 120000000}, // Actual baud: 57604, error +0.01%, 120 iterations
old: { 57600, 68, 12, 11, 120000000}, // Actual baud: 57545, error -0.10%, 420 iterations
new: { 115200, 47, 13, 5, 120000000}, // Actual baud: 115248, error +0.04%, 120 iterations
old: { 115200, 34, 12, 11, 120000000}, // Actual baud: 115090, error -0.10%, 315 iterations
new: { 230400, 19, 7, 5, 120000000}, // Actual baud: 230263, error -0.06%, 120 iterations
old: { 230400, 17, 12, 11, 120000000}, // Actual baud: 230179, error -0.10%, 210 iterations
new: { 250000, 30, 1, 0, 120000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 30, 1, 0, 120000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 5, 2, 1, 120000000}, // Actual baud: 1000000, error =0.00%, 3 iterations
old: {1000000, 4, 8, 7, 120000000}, // Actual baud: 1000000, error =0.00%, 210 iterations
new: {2000000, 3, 4, 1, 120000000}, // Actual baud: 2000000, error =0.00%, 8 iterations
old: {2000000, 2, 8, 7, 120000000}, // Actual baud: 2000000, error =0.00%, 210 iterations
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done :) |
bogdanm
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Dec 2, 2013
…lculation NXP targets: Improved baudrate calculation function
bridadan
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Jun 21, 2016
Resubmission of #92 but with SHA's in .lib files
yossi2le
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Jan 2, 2019
- "(uint32_t)APPLICATION_ADDRESS + 4" simply suppresses an warning from the
compiler (related to doing arithmetic on void* pointers).
- "applicationResetHandler" is now static, to avoid placing it on the stack, since
it is used after the stack pointer is set to the application's stack pointer.
- while(1) is needed for armcc. Without it, armcc insists to jump to the
application's entry point only *after* restoring the context of
"forwardControlToApplication":
806c: f380 8808 msr MSP, r0
8070: 481d ldr r0, [pc, ARMmbed#116] ; (80e8 <forwardControlToApplication+0xe8>)
8072: 6004 str r4, [r0, #0]
8074: 6828 ldr r0, [r5, #0]
8076: e8bd 4070 ldmia.w sp!, {r4, r5, r6, lr} ==> context restore
807a: 4700 bx r0 ==> jump to application
This changes the application's initial stack pointer. Because of this, the
cloud client example doesn't start anymore when concatenated with the bootloader.
With "while(1);" in place, we get the right behaviour:
806a: f380 8808 msr MSP, r0
806e: 481d ldr r0, [pc, ARMmbed#116] ; (80e4 <forwardControlToApplication+0xe4>)
8070: 6004 str r4, [r0, #0]
8072: 6828 ldr r0, [r5, #0]
8074: 4780 blx r0 ==> jump to application
Tested with armcc 5.03 update 3. Also tested that the GCC compilation still works
with these changes in place.
artokin
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to artokin/mbed-os
that referenced
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Feb 25, 2019
…cc3d 227cc3d Merge pull request ARMmbed#120 from ARMmbed/sync_with_mbedos_2 88894d1 Follow Mbed OS coding style f3db9a1 (via Mbed OS) Add mbedtls platform setup and teardown to modules 5feb8dd Merge pull request ARMmbed#119 from ARMmbed/sync_with_MbedOS 10d5054 (via Mbed OS) Add missing mbed_lib.json for frameworks and nanostack a344676 Remove references to yotta (ARMmbed#118) 610afda Remove excess tracing (ARMmbed#117) 53382d6 Merge pull request ARMmbed#116 from ARMmbed/IOTTHD-1608 15889cb Use Mbed OS coding style d6eff5c Clarify function signature 587e8de Update message prevalidation API 46f86d4 Add API to set callback for CoAP msg prevalidation (ARMmbed#115) 0eb6630 Merge pull request ARMmbed#114 from ARMmbed/sync_with_mbed_os f75732b (split) Add unit tests for TLSSocket and TLSSocketWrapper git-subtree-dir: features/nanostack/coap-service git-subtree-split: 227cc3d
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Uses 100% integer math, delivers more accurate results with fewer iterations in less time.
Since it seems most of the NXP chips use identical math, I have also altered the other targets in this commit.
If there are non-NXP chips which use a similar serial block, consider porting to those as well
Comparison:
new: { 9600, 625, 1, 0, 96000000}, // Actual baud: 9600, error =0.00%, 1 iterations
old: { 9600, 625, 1, 0, 96000000}, // Actual baud: 9600, error =0.00%, 0 iterations
new: { 38400, 125, 4, 1, 96000000}, // Actual baud: 38400, error =0.00%, 8 iterations
old: { 38400, 81, 14, 13, 96000000}, // Actual baud: 38409, error +0.02%, 420 iterations
new: { 57600, 81, 7, 2, 96000000}, // Actual baud: 57613, error +0.02%, 120 iterations
old: { 57600, 54, 14, 13, 96000000}, // Actual baud: 57613, error +0.02%, 315 iterations
new: { 115200, 27, 14, 13, 96000000}, // Actual baud: 115226, error +0.02%, 120 iterations
old: { 115200, 27, 14, 13, 96000000}, // Actual baud: 115226, error +0.02%, 210 iterations
new: { 230400, 23, 15, 2, 96000000}, // Actual baud: 230179, error -0.10%, 120 iterations
old: { 230400, 17, 15, 8, 96000000}, // Actual baud: 230179, error -0.10%, 525 iterations
new: { 250000, 24, 1, 0, 96000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 24, 1, 0, 96000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 6, 1, 0, 96000000}, // Actual baud: 1000000, error =0.00%, 1 iterations
old: {1000000, 6, 1, 0, 96000000}, // Actual baud: 1000000, error =0.00%, 0 iterations
new: {2000000, 3, 1, 0, 96000000}, // Actual baud: 2000000, error =0.00%, 1 iterations
old: {2000000, 3, 1, 0, 96000000}, // Actual baud: 2000000, error =0.00%, 0 iterations
new: { 9600, 514, 15, 4, 100000000}, // Actual baud: 9600, error =0.00%, 110 iterations
old: { 9600, 337, 15, 14, 100000000}, // Actual baud: 9593, error -0.07%, 1365 iterations
new: { 38400, 93, 4, 3, 100000000}, // Actual baud: 38402, error +0.01%, 120 iterations
old: { 38400, 85, 12, 11, 100000000}, // Actual baud: 38363, error -0.10%, 525 iterations
new: { 57600, 62, 4, 3, 100000000}, // Actual baud: 57604, error +0.01%, 120 iterations
old: { 57600, 61, 9, 7, 100000000}, // Actual baud: 57633, error +0.06%, 840 iterations
new: { 115200, 31, 4, 3, 100000000}, // Actual baud: 115207, error +0.01%, 120 iterations
old: { 115200, 31, 4, 3, 100000000}, // Actual baud: 115207, error +0.01%, 525 iterations
new: { 230400, 19, 7, 3, 100000000}, // Actual baud: 230263, error -0.06%, 120 iterations
old: { 230400, 19, 7, 3, 100000000}, // Actual baud: 230263, error -0.06%, 735 iterations
new: { 250000, 25, 1, 0, 100000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 25, 1, 0, 100000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 5, 4, 1, 100000000}, // Actual baud: 1000000, error =0.00%, 8 iterations
old: {1000000, 5, 4, 1, 100000000}, // Actual baud: 1000000, error =0.00%, 315 iterations
new: {2000000, 2, 9, 5, 100000000}, // Actual baud: 2008929, error +0.45%, 120 iterations
old: {2000000, 2, 9, 5, 100000000}, // Actual baud: 2008929, error +0.45%, 315 iterations
new: { 9600, 625, 4, 1, 120000000}, // Actual baud: 9600, error =0.00%, 8 iterations
old: { 9600, 404, 15, 14, 120000000}, // Actual baud: 9602, error +0.02%, 1575 iterations
new: { 38400, 179, 11, 1, 120000000}, // Actual baud: 38408, error +0.02%, 120 iterations
old: { 38400, 101, 15, 14, 120000000}, // Actual baud: 38409, error +0.02%, 525 iterations
new: { 57600, 93, 5, 2, 120000000}, // Actual baud: 57604, error +0.01%, 120 iterations
old: { 57600, 68, 12, 11, 120000000}, // Actual baud: 57545, error -0.10%, 420 iterations
new: { 115200, 47, 13, 5, 120000000}, // Actual baud: 115248, error +0.04%, 120 iterations
old: { 115200, 34, 12, 11, 120000000}, // Actual baud: 115090, error -0.10%, 315 iterations
new: { 230400, 19, 7, 5, 120000000}, // Actual baud: 230263, error -0.06%, 120 iterations
old: { 230400, 17, 12, 11, 120000000}, // Actual baud: 230179, error -0.10%, 210 iterations
new: { 250000, 30, 1, 0, 120000000}, // Actual baud: 250000, error =0.00%, 1 iterations
old: { 250000, 30, 1, 0, 120000000}, // Actual baud: 250000, error =0.00%, 0 iterations
new: {1000000, 5, 2, 1, 120000000}, // Actual baud: 1000000, error =0.00%, 3 iterations
old: {1000000, 4, 8, 7, 120000000}, // Actual baud: 1000000, error =0.00%, 210 iterations
new: {2000000, 3, 4, 1, 120000000}, // Actual baud: 2000000, error =0.00%, 8 iterations
old: {2000000, 2, 8, 7, 120000000}, // Actual baud: 2000000, error =0.00%, 210 iterations