AK4184A Datasheet, PDF (18/36 Pages) Asahi Kasei Microsystems – TSC with Keypad Scanner and GPIO Expander

[AK4184A]
■ λονεΫϦʔϯίϯτϩʔϥ੍ޚγʔέϯε



A/DೖྗͷαϯϓϦϯάɺA/Dม׵ͷλΠϛϯάΛ Figure 8 ʹࣔ͠·͢ɻCSN pin ↓ͰDOUT͸Hi-Zঢ়ଶ͔Β“L”
ʹͳΓ·͢ɻAK4184A͸ɺ4 ϏοτͷλονεΫϦʔϯ੍ޚίϚϯυΛಡΈࠐΈ·͢ɻ੍ޚίϚϯυऴྃޙɺ
ΫϩοΫೖྗ͕ऴྃ(32SCLK)͢Δ·ͰɺDIN pin = “L”ͱ͠ͳ͚Ε͹ͳΓ·ͤΜɻελʔτ(S bit)Ϗοτ͸ɺλ
ονεΫϦʔϯίϚϯυͷ։࢝Λೝࣝ͢ΔͨΊඞͣ“1”Ͱͳ͚Ε͹ͳΓ·ͤΜŇ Sampling1 ·ͨ͸Sampling2 ͷ
αϯϓϦϯάͰؒظA/DίϯόʔλͷೖྗͷαϯϓϦϯάΛߦ͍·͢ɻஞ࣍ൺֱܕADίϯόʔλ͸ɺSCLK
ʹಉͯ͠ظม׵Λߦ͍·͢ɻSCLK6 ↓͔ΒADม׵Λ։࢝͠ɺSCLK20 ↓͔ΒMSBϑΝʔετͰ 12bitͷσʔλ
Λग़ྗ͍͖ͯ͠·͢ɻ
αϯϓϦϯάͷλΠϛϯά͸ɺPD bit ʹΑΓܾ·Γ·͢ɻ
લճͱࠓճͷ A1 bit, A0 bit ͕มԽ͠ͳ͍৔߹(࿈ଓͰಉ࣠͡Λଌఆ)ɺલճઃఆ͕ PD bit = “0”ͷ࣌ͷαϯϓϦ
ϯάؒظ͸ɺSampling2 Ͱ͢ɻલճઃఆ͕ PD bit = “1”ͷ࣌ͷαϯϓϦϯάؒظ͸ɺSampling1 + Sampling2(CSN
↓ʙSCLK6 ↓)Ͱ͢ɻ͜ͷ৔߹ɺCSN pin ↓͔Β࠷ॳͷ SCLK pin ↓·Ͱͷ࣌ؒΛԆ͹͢ࣄͰαϯϓϦϯά࣌ؒ
(Sampling1)Λ௕͘͢Δ͜ͱ͕ՄೳͰ͢ɻ
A1 bit ͱ A0 bit ͕ࠓճͷઃఆͰ੾Γସ͑Δ(࣠ͷมߋ)৔߹͸ɺPD bit ʹؔ܎ͳ͘ࠓճઃఆ࣠(A1 bit, A0 bit)ʹର
ͯ͠ଌఆΛߦ͍·͢ɻαϯϓϦϯάؒظ͸ɺSampling2 Ͱ͢ɻલճઃఆ PD bit = “1”ͷ৔߹ Sampling1 ͷͰؒظ
͸ࠓճઃఆͱ͸ҧ͏࣠Λଌఆ͍ͯ͠·͢ͷͰ༗ޮͳαϯϓϦϯάؒظ͸ Sampling2 ͷΈͰ͢ɻ
಺෦ΩϟύγλʹిՙΛνϟʔδ͢ΔͨΊͷ࣌ؒ(αϯϓϦϯά࣌ؒ)͸ɺλονεΫϦʔϯͷιʔεΠϯϐʔ
μϯε ͼٴSCLK εϐʔυʹґଘ͠·͢ɻPD bit = “0”ઃఆͰ Sampling2 ۠ؒͷΈͷνϟʔδͰ͸࠷ऴిҐʹ
౸ୡ͠ͳ͍৔߹͸ɺPD bit = “1”ઃఆͰ࿈ଓͯ࣠͠ଌఆΛߦ͏͔ɺΫϩοΫΛ஗ͯ͘͠ητϦϯά࣌ؒΛे෼
֬อ͍ͯͩ͘͠͞ɻ
CSN
SCLK
1 2 3 4 5 6 7 8 9 14 16 17 18 19 20 21 22 23 24 25 29 30 31 32
DIN
S A1 A0 PD
Control Command
Hi-Z
DOUT
Touch Screen Driver SW
Previous PD bit
PD = “0”
Sampling2
PD = “1”
Sampling1 + Sampling2
A/D conversion
0
Hi-Z
D11 D10 D9 D8 D4 D3 D2 D1 D0
A/D Data
Current PD bit
PD = “0”
PD = “1”
PD = “1”
PD = “0”
Figure 9. Touch Screen Operation
MS0947-J-00
-18-
2008/04