MAXQ61CA MAXIM [Maxim Integrated Products], MAXQ61CA Datasheet - Page 20

• Manufacturer Part Number: MAXQ61CA
• Description: 16-Bit Microcontroller with Infrared Module
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 8. SPI Slave Communication Timing
16-Bit Microcontroller with Infrared Module
The microcontroller provides port pins for general-pur-
pose I/O that have the following features:
• CMOS output drivers
• Schmitt trigger inputs
• Optional weak pullup to V
While the microcontroller is in a reset state, all port pins
become high impedance with both weak pullups and
input buffers disabled, unless otherwise noted.
From a software perspective, each port appears as a
group of peripheral registers with unique addresses.
Special function pins can also be used as general-pur-
pose I/O pins when the special functions are disabled.
For a detailed description of the special functions avail-
able for each pin, refer to the MAXQ610 User’s Guide.
An external quartz crystal or a ceramic resonator can be
connected between HFXIN and HFXOUT, as illustrated
in Figure 9.
20
mode
_____________________________________________________________________________________
CKPOL/CKPHA
CKPOL/CKPHA
0/1 OR 1/0
0/0 OR 1/1
SCLK
SCLK
MOSI
MISO
SSEL
General-Purpose I/O
On-Chip Oscillator
t
SSE
DD
SHIFT
when operating in input
t
MSB
SIS
SAMPLE
MSB
t
SCK
t
SCH
SHIFT
t
SOV
t
SCL
MSB-1
SAMPLE
MSB-1
Figure 9. On-Chip Oscillator
Noise at HFXIN and HFXOUT can adversely affect on-
chip clock timing. It is good design practice to place the
crystal and capacitors near the oscillator circuitry and
connect HFXIN and HFXOUT to ground with a direct
short trace. The typical values of external capacitors vary
with the type of crystal to be used and should be initially
selected based on load capacitance as suggested by
the manufacturer.
t
SIH
C1
C2
t
RF
LSB
HFXOUT
HFXIN
LSB
V
DD
R
F
t
SD
R
C1 = C2 = 12pF
F
= 1MI Q50%
t
SLH
t
SSH
CLOCK CIRCUIT
STOP