SH7670 Datasheet, PDF (933/1292 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

Section 20 Host Interface (HIF)
20.9 Interface When External Device Power is Cut Off
When the power supply of an external device interfacing with the HIF is cut off, intermediate
levels may be applied to the HIF input pins or the HIF output pins may drive an external device
not powered, thus causing the device to be damaged. The HIFEBL pin is provided to prevent this
from happening. The system power monitor block controls this pin in synchronization with the
cutoff of the external device power so that all pins of this module excluding HIFMD can be set to
the high-impedance state. Figure 20.11 shows an image of high-impedance control of the HIF
pins. Table 20.8 lists the input/output control for the HIF pins.
HIFD15 to HIFD00
HIFCS
HIFRS
HIFWR
HIFRD
HIFMD
HIFINT
HIFDREQ
HIFRDY
HIFEBL
Figure 20.11 Image of High-Impedance Control of HIF Pins by HIFEBL Pin
Rev. 1.00 Nov. 14, 2007 Page 907 of 1262
REJ09B0437-0100