FT800 Series Programmer Guide
Version 2.1
Document Reference No.: BRT_000030 Clearance No.: BRT#037
237
Copyright © Bridgetek Limited
5.50
CMD_SKETCH - start a continuous sketch update
After the sketch command, the co-processor engine continuously samples the touch
inputs and paints pixels into a bitmap, according to the touch (x, y). This means that the
user touch inputs are drawn into the bitmap without any need for MCU work. Command
CMD_STOP stops the sketch process.
Note that only one of CMD_SKETCH, CMD_SCREENSAVER, or CMD_SPINNER can be
active at one time.
This command is applicable for FT800 and FT801 users is recommended to use
CMD_CSKETCH since the optimization has been done for capacitive touch.
C prototype
void cmd_sketch( int16_t x,
int16_t y,
uint16_t w,
uint16_t h,
uint32_t ptr,
uint16_t format );
Parameters
x
x-coordinate of sketch area top-left, in pixels
y
y-coordinate of sketch area top-left, in pixels
w
Width of sketch area, in pixels
h
Height of sketch area, in pixels
ptr
Base address of sketch bitmap
format
Format of sketch bitmap, either L1 or L8
Description
Please note that update frequency of bitmap data in graphics memory depends on
sampling frequency of ADC built-in circuit of FT800, which is up to 1000 Hz.