diff options
| author | Marti Bolivar <mbolivar@leaflabs.com> | 2011-03-22 16:59:29 -0400 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@leaflabs.com> | 2011-03-24 07:25:14 -0400 |
| commit | 296b1188bfb8cf28466b95f1dd0fde309b1f9399 (patch) | |
| tree | b0ed2b9fecb2da85266e6b2b88c6fe31bb0ca2c8 /notes/vga.txt | |
| parent | 68b57d90007a234e6a2fc82f6b9402fb6b77ef34 (diff) | |
Initial timer refactor.
Basic PWM works. Had some problems in testing that might be due to
USART bugs.
HardwareTimer has been removed from the build for now; I will
re-implement it in terms of the new libmaple API, but consider it
deprecated. Let's come up with something better.
Servo is implemented in terms of HardwareTimer, so it also has been
temporarily removed from the build.
pwmWrite() likely got a little bit less inefficient due to
indirection, but the PIN_MAPs shrank by a pointer per PinMapping.
Diffstat (limited to 'notes/vga.txt')
| -rw-r--r-- | notes/vga.txt | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/notes/vga.txt b/notes/vga.txt index d75281a..43b6830 100644 --- a/notes/vga.txt +++ b/notes/vga.txt @@ -7,8 +7,7 @@ gpio_write_bit() is about 360ns (2.78MHz) Writing to GPIO?_BASE is about 60ns (16.6MHz -> 18MHz) -pwm write 0x0001 is about 30ns (33MHz) with prescaler as 1 (default) -pwm write 0x0001 is about 14ns (72MHz) with prescaler as 0 (!) +PWM write 0x0001 is about 14ns (72MHz) with prescaler as 0 (!) VGA Timing ------------------------------------------------------------------------------ @@ -34,9 +33,3 @@ Crude 640x480 directions: 11 lines front porch 2 lines Vsync (low) 31 lines back porch - -Currently, setting vs. clearing GPIO registers seems to take a different amount -of time? Or perhaps i'm not analyzing branching correctly. Regardless, if you -SET 100x times then UNSET on one line, then UNSET 100x then SET the next line, -the two changes in color will generally not line up. - |