MAX1233ETI+T Maxim Integrated Products, MAX1233ETI+T Datasheet - Page 18

• Manufacturer Part Number: MAX1233ETI+T
• Description: IC CNTRLR TOUCH 28-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Resistiver

Specifications of MAX1233ETI+T

• Touch Panel Interface: 4-Wire
• Number Of Inputs/keys: 1, 4 x 4 Keypad
• Resolution (bits): 8, 10, 12 b
• Data Interface: MICROWIRE™, QSPI™, Serial, SPI™
• Data Rate/sampling Rate (sps, Bps): 50k
• Voltage Reference: External, Internal
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Applications: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
PENIRQ returns high only after a touch-screen scan is
completed. PENIRQ does not go low again until one of
the touch-screen data registers is read. Figures 8a and
8b show the timing diagrams for the PENIRQ pin.
The KEYIRQ output can be used to alert the host con-
troller of a key press. The KEYIRQ output is normally
high and goes low after a key press is detected.
KEYIRQ returns high only after a key-press scan is
completed. KEYIRQ does not go low again until one of
the key-press data registers is read. Figures 9a and 9b
show the timing diagrams for the KEYIRQ pin.
BUSY informs the host processor that a scan is in
progress. BUSY is normally high and goes low and
stays low during each functional operation. The host
controller should wait until BUSY is high again before
using the serial interface.
The MAX1233/MAX1234 interface to the host controller
through a standard 3-wire serial interface at up to
10MHz. DIN and CS are the digital inputs to the
MAX1233/MAX1234. DOUT is the serial data output.
Data is clocked out at the SCLK falling edge and is
high impedance when CS is high. When performing an
ADC scan, CS must de-assert high before the end of
the first conversion, otherwise the conversion results
will not be stored. PENIRQ and KEYIRQ communicate
interrupts from the touch-screen and keypad controllers
to the host processor when a screen touch or a key
press is detected. BUSY informs the host processor that
a scan is in progress. In addition to these digital I/Os, the
row and column pins of the keypad controller can be
programmed as GPIO pins.
The MAX1233/MAX1234 are controlled by reading from
and writing to registers through the 3-wire serial inter-
face. These registers are addressed through a 16-bit
command that is sent prior to the data. The command
is shown in Table 2.
The first 16 bits after the falling edge of CS contain the
command word. The command word begins with an
R/W bit, which specifies the direction of data flow on
the serial bus. Bits 14 through 7 are reserved for future
use. Bit 6 specifies the page of memory in which the
Table 2. Command Word Format
18
BIT15
MSB
R/W
______________________________________________________________________________________
BIT14 BIT13 BIT12 BIT11 BIT10
RES
RES
Keypad Interrupt Request (KEYIRQ)
RES
Busy Indicator ( BUSY )
Communications Protocol
RES
Digital Interface
RES
BIT9
RES
BIT8
RES
BIT7
RES
desired register is located. The last 6 bits specify the
address of the desired register. The next 16 bits of data
are read from or written to the address specified in the
command word. After 32 clock cycles, the interface
automatically increments its address pointer and con-
tinues reading or writing until the rising edge of CS, or
until it reaches the end of the page.
Figure 9a. Timing Diagram for Key-Press-Initiated Debounce
Scan
Figure 9b. Timing Diagram for Host-Initiated Keypad
Debounce Scan
KEYIRQ
KEYIRQ
DOUT
BUSY
BUSY
DOUT
DIN
R_
CS
CS
R_
PAGE
BIT6
ADD5
BIT5
ADD4
BIT4
ADD3
BIT3
ADD2
BIT2
ADD1
BIT1
TOUCH-
SCREEN
DATA
TOUCH-
SCREEN
DATA
ADD0
BIT0
LSB
DATA
READ
DATA
READ