Cypress CY7C63413C, CY7C63513C, CY7C63613C - page 14

CY7C63413C
CY7C63513C
CY7C63613C
Document #: 38-08027 Rev. *B Page 14 of 32
The DAC port provides the CY7C63513C with 8 program-
mable current sink I/O pins. Writing a “1” to a DAC I/O pin
disables the output current sink (Isink DAC) and drives the I/O
pin HIGH through an integrated 14 Kohm resistor. When a “0”
is written to a DAC I/O pin, the Isink DAC is enabled and the
pull-up resistor is disabled. A “0” output will cause the Isink
DAC to sink current to drive the output LOW. The amount of
sink current for the DAC I/O pin is programmable over 16
values based on the contents of the DAC Isink Register for that
output pin. DAC[1:0] are the two high current outputs that are
programmable from a minimum of 3.2 mA to a maximum of 16
mA (typical). DAC[7:2] are low current outputs that are
programmable from a minimum of 0.2 mA to a maximum of 1.0
mA (typical).
When a DAC I/O bit is written as a “1,” the I/O pin is either an
output pulled high through the 14 Kohm resistor or an input
with an internal 14 Kohm pull-up resistor. All DAC port data bits
are set to “1” during reset.
DAC Port Interrupts
A DAC port interrupt can be enabled/disabled for each pin
individually. The DAC Port Interrupt Enable register provides
this feature with an interrupt mask bit for each DAC I/O pin.
Writing a “1” to a bit in this register enables interrupts from the
corresponding bit position. Writing a “0” to a bit in the DAC Port
Interrupt Enable register disables interrupts from the corre-
sponding bit position. All of the DAC Port Interrupt Enable
register bits are cleared to “0” during a reset.
As an additional benefit, the interrupt polarity for each DAC pin
is programmable with the DAC Port Interrupt Polarity register.
Writing a “0” to a bit selects negative polarity (falling edge) that
will cause an interrupt (if enabled) if a falling edge transition
occurs on the corresponding input pin. Writing a “1” to a bit in
this register selects positive polarity (rising edge) that will
cause an interrupt (if enabled) if a rising edge transition occurs
on the corresponding input pin. All of the DAC Port Interrupt
Polarity register bits are cleared during a reset.
DAC Isink Registers
Each DAC I/O pin has an associated DAC Isink register to
program the output sink current when the output is driven
LOW. The first Isink register (0x38) controls the current for
DAC[0], the second (0x39) for DAC[1], and so on until the Isink
register at 0x3F controls the current to DAC[7].
Table 13.DAC Port Data
Addr: 0x30 DAC Port Data
Low current outputs
0.2 mA to 1.0 mA typical High current outputs 3.2 mA to 16 mA typical
DAC[7] DAC[6] DAC[5] DAC[4] DAC[3] DAC[2] DAC[1] DAC[0]
R/W R/W R/W R/W R/W R/W R/W R/W
Table 14.DAC Port Interrupt Enable
Addr: 0x31 DAC Port Interrupt Enable
DAC[7] DAC[6] DAC[5] DAC[4] DAC[3] DAC[2] DAC[1] DAC[0]
WWWWWWWW
Table 15.DAC Port Interrupt Polarity
Addr: 0x32 DAC Port Interrupt Polarity
DAC[7] DAC[6] DAC[5] DAC[4] DAC[3] DAC[2] DAC[1] DAC[0]
WWWWWWWW
Table 16.DAC Port Isink
Addr: 0x38-0x3F DAC Port Interrupt Polarity
Reserved Isink Value
Isink[3] Isink[2] Isink[1] Isink[0]
W W W W
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