DM562P
V.90 Integrated Data/ Fax/Voice/Speakerphone
Modem Device Single Chip with Memory Built in
Preliminary
29
Version: DM562P-DS-P02
February 28, 2001
PCI function power management state
The DM6588 supports PCI function power states D0,
D3(hot), D3(cold). Additional PCI signal PME# to pin
A19 of the standard PCI connector.
PME Context
PME (power Management Event) context is defined
as the functional state information and logic required
to generate power management events(PMEs), report
PME status, and enable PMEs.
For MODEM, PME context consists of PME_En bit,
PME_Status bit , Ring Detect ,and Ring to PME
circuit.
PCI MODEM Power Management Operation
During a true power-on situation (no auxiliary and
normal power), PME_En = 0 to avoid to assert PME#.
When assert RST#, the pci configuration space is set
to default value except PME context which must
preserve.
DM6588 can not assert PME# from D0. But can
Assert PME# from D3(hot) and D3(cold). Hence the
Ring to PME# circuit must check the power state. If
ring comes at D0 power state, it can not assert PME#.
Software will enable its use by setting the PME_En bit
in the PMCSR.
It must continue to assert PME# until software either
clears the PME_En bit or clears the PME_Status bit.
Before enter D3(cold) state, host must :
1. Write 1 into PME_Status bit to clear previous
PME status
2. Write 1 into PME_En bit to enable PME
function.
3. Write 3 into Power_state
4. Power off PCI bus.
When Ring comes, Ring to PME# circuit check if
PME_EN=1 and Power_staus <>0. If yes, assert
PME# and set PME_Status=1.
When host detect PME# asserted, it will power up PCI
bus and assert RST# to initialize pci modem. At the
same time, it write 1 into PME_En bit or PME_Status
bit to stop PME#.
Before enter D3(hot) state, host must :
5. Write 1 into PME_Status bit to clear previous
PME status
6. Write 1 into PME_En bit to enable PME
function.
7. Write 3 into Power_state
When Ring come, Ring to PME# circuit check if
PME_EN=1 and Power_staus <>0. If yes, assert
PME# and set PME_Status=1.
When host detect PME# asserted, it will re-initialize
pci modem and set Power_State=0 to return D0 state.
At the same time, it write 1 into PME_En bit or
PME_Status bit to stop PME#.
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