go-embedded/embd
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controller: add more descriptive docs to the hd44780 exported variables

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This commit is contained in:
Matthew Dale 2015-04-09 00:52:27 -07:00
parent 915b3b76a7
commit 3254f15093
1 changed files with 13 additions and 6 deletions
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19
controller/hd44780/hd44780.go
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@ -23,19 +23,25 @@ type entryMode byte
type displayMode byte type displayMode byte
type functionMode byte type functionMode byte
// RowAddress defines the DDRAM address of the first column of each row, up to 4 rows. // RowAddress defines the cursor (DDRAM) address of the first column of each row, up to 4 rows.
// You must use the RowAddress value that matches the number of columns on your character display
// for the SetCursor function to work correctly.
type RowAddress [4]byte type RowAddress [4]byte
var ( var (
RowAddress16Col RowAddress = [4]byte{0x00, 0x40, 0x10, 0x50} // row addresses for 16-column displays // RowAddress16Col are row addresses for a 16-column display
RowAddress20Col RowAddress = [4]byte{0x00, 0x40, 0x14, 0x54} // row addresses for 20-column displays RowAddress16Col RowAddress = [4]byte{0x00, 0x40, 0x10, 0x50}
// RowAddress20Col are row addresses for a 20-column display
RowAddress20Col RowAddress = [4]byte{0x00, 0x40, 0x14, 0x54}
) )
// BacklightPolarity defines the polarity of the backlight switch, either positive or negative // BacklightPolarity is used to set the polarity of the backlight switch, either positive or negative.
type BacklightPolarity bool type BacklightPolarity bool
const ( const (
// Negative indicates that the backlight is active-low and must have a logical low value to enable.
Negative BacklightPolarity = false Negative BacklightPolarity = false
// Positive indicates that the backlight is active-high and must have a logical high value to enable.
Positive BacklightPolarity = true Positive BacklightPolarity = true
writeDelay = 37 * time.Microsecond writeDelay = 37 * time.Microsecond
@ -187,6 +193,7 @@ func (controller *HD44780) lcdInit() error {
} }
// DefaultModes are the default initialization modes for an HD44780. // DefaultModes are the default initialization modes for an HD44780.
// ModeSetters passed in to a constructor will override these default values.
var DefaultModes []ModeSetter = []ModeSetter{ var DefaultModes []ModeSetter = []ModeSetter{
FourBitMode, FourBitMode,
OneLine, OneLine,
@ -553,14 +560,14 @@ type I2CPinMap struct {
} }
var ( var (
// Standard pin mapping for an MJKDZ-based I²C backpack. // MJKDZPinMap is the standard pin mapping for an MJKDZ-based I²C backpack.
MJKDZPinMap I2CPinMap = I2CPinMap{ MJKDZPinMap I2CPinMap = I2CPinMap{
RS: 6, RW: 5, EN: 4, RS: 6, RW: 5, EN: 4,
D4: 0, D5: 1, D6: 2, D7: 3, D4: 0, D5: 1, D6: 2, D7: 3,
Backlight: 7, Backlight: 7,
BLPolarity: Negative, BLPolarity: Negative,
} }
// Standard pin mapping for a PCF8574-based I²C backpack. // PCF8574PinMap is the standard pin mapping for a PCF8574-based I²C backpack.
PCF8574PinMap I2CPinMap = I2CPinMap{ PCF8574PinMap I2CPinMap = I2CPinMap{
RS: 0, RW: 1, EN: 2, RS: 0, RW: 1, EN: 2,
D4: 4, D5: 5, D6: 6, D7: 7, D4: 4, D5: 5, D6: 6, D7: 7,