z893232yfsc ZiLOG Semiconductor, z893232yfsc Datasheet - Page 16

• Manufacturer Part Number: z893232yfsc
• Description: 16-bit Digital Signal Processors
• Manufacturer: ZiLOG Semiconductor

EXT Register Assignments (Continued)
Interrupt Status Bits
When read, these bits provide interrupt information to
identify the source for INT2, or when the DSP works in
Pending Interrupt mode, to warn the DSP of pending
interrupts. These bits also clear the interrupt status bits.
Writing 1 will clear these bits.
Wait-State Register
The Wait-State Control Register enables insertion of Wait
States when the DSP needs to access slow, inexpensive
peripherals. This software-controlled register enables
insertion of one Wait State when accessing EXT bus. (One
Wait State gives 100 nsec access time instead of 50 nsec
16
Ext 7 Reg
D15 D14 D13
D12
D11
D10
Figure 8. EXT7 Register Bit Assignment
D9
P R E L I M I N A R Y
D8
D7
D6
D5
access time with a 20 MHz oscillator.) When more than one
Wait State is needed, an input pin (WAIT) coupled with
external logic can support more than one Wait State. The
Wait-State Control Register enables mapping specific EXT
register (from EXT0 to EXT6) and specific operation (read
or write) to include insertion of one Wait State. EXT7 is
always internal register, therefore no Wait State is needed
for EXT7.
Note:
When the programmer switches banks it is important to change the Wait
State mapping of the EXT registers to match the desired Wait State
mapping of the new bank.
D4
D3
D2
D1
D0
Bank Select
Interrupt Status Bits
Reserved
0000 : Bank0
0001 : Bank1
1111 : Bank15
Bit 4 = A/D Finish Interrupt
Bit 5 = SPI Interrupt
Bit 6 = Timer0 Interrupt
Bit 7 = Timer1 Interrupt
Bit 8 = Timer2 Interrupt
Bit 9 = INT0 (H/W) Interrupt
Bit 10 = INT1 (H/W) Interrupt
Bit 11 = INT2 (H/W) Interrupt
:
:
16-B
DS95DSP0101 Q4/95
IT
D
IGITAL
S
IGNAL
Z89323/373/393
P
ROCESSORS