Motorola DSP56012 사용자 설명서

transfer request pin of a DMA controller, or a control input of external circuitry. 
HOREQ is asserted when an enabled request occurs in the HI. HOREQ is deasserted 
when the enabled request is cleared or masked, DMA HACK is asserted, or the DSP 
is reset. HOREQ can be programmed as a GPIO pin (not open-drain) called PB13 
when the HI is not being used.

The Port B control register allows the user to program the Host Acknowledge 
(HACK) input independently of the other HI pins. When the port is configured for 
GPIO, this input acts as a GPIO pin called PB14. When the port is defined as the HI, 
the user can manipulate the Port B control register to configure this input as either 
PB14, or as the HACK pin. 

configurations.

HACK can act as a data strobe for HI DMA data transfers (See 

on page 4-42). Or, if HACK is used as an MC68000 host interrupt acknowledge, it 
enables the host Interrupt Vector Register (IVR) on the host data bus (H[7:0]) if 
HOREQ is asserted (See 

pins are ignored and the state of the HI is not affected. 

 HACK should always be pulled high when it is not in use.

0

0

Parallel I/O (Reset Condition)

0

1

HI

1

0

HI (HACK is defined as GPIO)

1

1

Reserved