AK4185 AKM [Asahi Kasei Microsystems], AK4185 Datasheet - Page 22

• Manufacturer Part Number: AK4185
• Manufacturer: AKM [Asahi Kasei Microsystems]

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The AK4185 has pen interrupt function to detect the pen touch. Pen interrupt function is enabled at power-down state. The
YN pin (4-wire) or BL pin (5-wire) is connected to VSS at the PEN interrupt enabled state. And the XP pin (4-wire) or
WIPER pin (5-wire) is pulled up via an internal resistor (R
WIPER pin (5-wire) inside. If touch plate is pressed by a pen, the current flows via <VDD> - <Ri> - <X+> - <Y->
(4-wire). If 5-wire, via <VDD> - <Ri> - <WIPER> - <BL>. The resistance of the plate is generally 1kΩ or less,
PENIRQN is forced to “L” level. If the pen is released, PENIRQN returns “H” level because two plates are disconnected,
and the current does not flow via two plates.
If the plate is touched with a pen or finger, PENIRQN changes to “L” at CSN = “H” that PENIRQN is normality enable.
PENIRQN is disabled during executing internal sequence (please see
(Internal Clock
The operation of PENIRQN is related to PD0 bit. PD0 bit is updated at the rising edge of 8th SCLK (please see
Power-down
command. When CSN is “L”, PENIRQN is disabled during executing internal sequence (please see
Controller Control Sequence (Internal Clock
The behavior of PENIRQN is related to the combination of the last selected analog input channel, and the last PD0 bit. If
the last PD0 bit was set to “0”, PENIRQN is “H” while the plate is not pressed and “L” while the plate is pressed
regardless of the last analog input. If the last PD0 bit was set to “1”, the last analog input decides the level of PENIRQN.
If the last analog input channel is touch screen (X, Y, Z1, Z2 or WIPER), PENIRQN is “L” for all the time in this period
regardless of the touched/non-touched state. On the other hand, if the last analog input channel is not touch screen
(temperature or auxiliary), PENIRQN is “H” for all the time in this period regardless of the touched/non-touched state.
The behavior of PENIRQN is related to the selected analog input and the last PD0 bit. If the current PD0 bit is set to “0”
and the touch screen is selected as analog input, PENIRQN is forced to “L” regardless of the touched/non-touched state. If
the temperature or auxiliary input is selected as the input channel, PENIRQN is forced to “H” regardless of the
touched/non-touched state. If the current PD0 bit is set to “1”, PENIRQN is forced to “H” regardless of the analog input
and the touched/non-touched state.
The behavior of PENIRQN is related to the combination of the current selected analog input channel, and the current PD0
bit. If the current PD0 bit set “0”, PENIRQN is “H” while the plate is not pressed and “L” while the plate is pressed
regardless of the current selected analog input. If the current PD0 bit set “1”, the current analog input decides the
operation of PENIRQN. If the current analog input channel is touch screen, PENIRQN is “L” for all the time in this period
regardless of the touched/non-touched state. On the other hand, if the current analog input is temperature or auxiliary
input, PENIRQN is “H” for all the time in this period regardless of the touched/non-touched state.
It is recommended that the micro controller mask the pseudo-interrupts while the control command is issued or A/D data
is output.
In continuous mode, AK4185 repeats behavior the period from the 5th SCLK↓ to the 21st SCLK↓ after output command.
Therefore, it must be noted that PENIRQN is valid only 1SCLK (equivalent the period from the 20th SCLK↓ to the 21st
SCLK↓) when PD0 bit is “0”. Generally recommend to execute continuous mode after PD0 bit is set “1”.
MS0954-E-00
iii.
ii.
Pen Interrupt
i.
The period from CSN↓ to the 5th SCLK↓
The period from the 5th SCLK↓ to the 20th SCLK↓ on CSN = “L” (8bit Mode: to the 16th SCLK↓)
The period from the 20th SCLK↓ to CSN↑ (8bit Mode: from the 16th SCLK↓ to CSN↑)
Control” for the detail). Therefore, the last PD0 bit is valid until this timing and during setting the setup
Mode)”) and sleep mode is available (please see
Mode)”).
- 22 -
IRQ
: typ.50kΩ). PENIRQN is connected the XP pin (4-wire) or
“■ Sleep
“■ Touch Screen Controller Control Sequence
Mode”).
“■ Touch Screen
[AK4185]
“■
2008/05