DSP56857 datasheet(81/662 Pages) FREESCALE

81 / 662 page

Power, Ground and Peripheral Signals

Overview, Rev. 4

Freescale Semiconductor

2-13

HREQ

(HTRQ)

(GPIOB14)

Open Drain

Output

Open Drain

Output

Input / Output

Host Request—When the HI is programmed for

HRMS = 0 functionality, typically used on a

single-data-strobe bus, this open drain output is

used by HI to request service from the host

processor. The HREQ may be connected to an

interrupt request pin of a host processor, a transfer

request of a DMA controller, or a control input of

external circuitry. This pin is disconnected

internally when reset.

Transmit Host Request—This signal is the output

when the HI is programmed for HRMS = 1

functionality and is typically used on a

double-data-strobe bus.

Port B GPIO 14—This is a General Purpose I/O

pin when not configured for host port use.

—

HACK

(HRRQ)

(GPIOB15)

Input

Open Drain

Output

Input / Output

Host Acknowledge—When the HI is programmed

for the HRMS = 0 functionality, typically used on a

single-data-strobe bus, this input has two

functions: (1) provide a Host Acknowledge signal

for DMA transfers, or (2) to control handshaking

and provide a Host Interrupt Acknowledge

compatible with the MC68000 family processors.

This pin is disconnected internally when reset.

Receive Host Request—This signal is the output

when the HI is programmed for HRMS = 1

functionality, and it is typically used on a

double-data-strobe bus.

Port B GPIO 15—This is a General Purpose I/O

pin when not configured for host port use.

—

Table 2-6. Host Interface Eight (Continued)

Signal Name

Signal Type

Signal Description

853

Pins

854

Pins

855

Pins

857

Pins

858

Pins

DSP56857 датащи(PDF) 81 Page - Freescale Semiconductor, Inc

DSP56857 датащи(HTML) 81 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL