PC7410 datasheet(49/57 Pages) ETC2

49 / 57 page

0832F–HIREL–02/07

e2v semiconductors SAS 2007

PC7410

The COP header shown in Figure 14-6 on page 50 adds many benefits — breakpoints, watchpoints, reg-

ister and memory examination/modification, and other standard debugger features are possible through

this interface — and can be as inexpensive as an unpopulated footprint for a header to be added when

needed.

The COP interface has a standard header for connection to the target system, based on the 0.025"

square-post 0.100" centered header assembly (often called a Berg header). The connector typically has

pin 14 removed as a connector key.

There is no standardized way to number the COP header shown in Figure 14-6; consequently, many dif-

ferent pin numbers have been observed from emulator vendors. Some are numbered top-to-bottom then

left-to-right, while others use left-to-right then top-to-bottom, while still others number the pins counter

clockwise from pin 1 (as with an IC). Regardless of the numbering, the signal placement recommended

in Figure 14-6 is common to all known emulators.

The QACK signal shown in Figure 14-6 is usually connected to the PCI bridge chip in a system and is an

input to the PC7410 informing it that it can go into the quiescent state. Under normal operation this

occurs during a low-power mode selection. In order for COP to work, the PC7410 must see this signal

asserted (pulled down). While shown on the COP header, not all emulator products drive this signal. If

the product does not, a pull-down resistor can be populated to assert this signal. Additionally, some emu-

lator products implement open-drain type outputs and can only drive QACK asserted; for these tools, a

pull-up resistor can be implemented to ensure this signal is deasserted when it is not being driven by the

tool. Note that the pull-up and pull-down resistors on the QACK signal are mutually exclusive and it is

never necessary to populate both in a system. To preserve correct power-down operation, QACK should

be merged via logic so that it also can be driven by the PCI bridge.

PC7410 Datasheet(PDF) 49 Page - List of Unclassifed Manufacturers