CY7C63722C
CY7C63723C
CY7C63743C
FOR
FOR
Document #: 38-08022 Rev. *C
Page 8 of 49
8.2
Data Memory Organization
The CY7C637xxC microcontrollers provide 256 bytes of data
RAM. In normal usage, the SRAM is partitioned into four
areas: program stack, data stack, user variables and USB
endpoint FIFOs as shown below.
8.3
I/O Register Summary
I/O registers are accessed via the I/O Read (IORD) and I/O
Write (IOWR, IOWX) instructions. IORD reads the selected
port into the accumulator. IOWR writes data from the accumu-
lator to the selected port. Indexed I/O Write (IOWX) adds the
contents of X to the address in the instruction to form the port
address and writes data from the accumulator to the specified
port. Note that specifying address 0 with IOWX (e.g., IOWX
0h) means the I/O port is selected solely by the contents of X.
Note: All bits of all registers are cleared to all zeros on
reset, except the Processor Status and Control Register
(Figure 20-1). All registers not listed are reserved, and should
never be written by firmware. All bits marked as reserved
should always be written as 0 and be treated as undefined by
reads.
After reset
Address
8-bit DSP
8-bit PSP
0x00
Program Stack Growth
(User’s firmware moves DSP)
8-bit DSP
User Selected
Data Stack Growth
User Variables
0xE8
USB FIFO for Address A endpoint 2
0xF0
USB FIFO for Address A endpoint 1
0xF8
USB FIFO for Address A endpoint 0
Top of RAM Memory
0xFF
Figure 8-2. Data Memory Organization
Table 8-1. I/O Register Summary
Register Name
I/O Address
Read/Write
Function
Fig.
Port 0 Data
0x00
R/W
GPIO Port 0
12-2
Port 1 Data
0x01
R/W
GPIO Port 1
12-3
Port 2 Data
0x02
R
Auxiliary input register for D+, D–, VREG, XTALIN
12-8
Port 0 Interrupt Enable
0x04
W
Interrupt enable for pins in Port 0
21-4
Port 1 Interrupt Enable
0x05
W
Interrupt enable for pins in Port 1
21-5
Port 0 Interrupt Polarity
0x06
W
Interrupt polarity for pins in Port 0
21-6
Port 1 Interrupt Polarity
0x07
W
Interrupt polarity for pins in Port 1
21-7
Port 0 Mode0
0x0A
W
Controls output configuration for Port 0
12-4
Port 0 Mode1
0x0B
W
12-5
Port 1 Mode0
0x0C
W
Controls output configuration for Port 1
12-6
Port 1 Mode1
0x0D
W
12-7
[+] Feedback
[+] Feedback