Semiconductor integrated circuit and data processing system
View Patent ↗To enhance the speed of first access (read access different in word line from the previous access) to a multi-bank memory, multi-bank memory macro structures are used. Data are held in a sense amplifier for every memory bank. When access is hit to the held data, data latched by the sense amplifier are output to thereby enhance the speed of first access to the memory macro structures. Namely, each memory bank is made to function as a sense amplifier cache. To enhance the hit ratio of such a sense amplifier cache more greatly, an access controller self-prefetches the next address (an address to which a predetermined offset has been added) after access to a memory macro structure so that data in the self-prefetched address are preread by a sense amplifier in another memory bank.
1. A semiconductor circuit on a semiconductor chip comprising:
a first access port and a second access port;
a plurality of memory banks, which can be accessed through both said first access port and said second access port; and
an access priority judgment unit;
wherein each of said plurality of memory banks includes a plurality of word lines, a plurality of bit lines, a plurality of memory cells, and a sense amplifier circuit,
wherein said access priority judgment unit gives priority to one of said first and second access ports over the other of said first and second access ports when said first and second access ports access a same memory bank of said plurality of memory banks, and
wherein said access priority judgment unit allows parallel access to said first and second access ports when said first and second access ports access different memory banks respectively.
2. The semiconductor circuit according to claim 1 ,
wherein said plurality of memory banks each further includes global bit lines coupled to said plurality of bit pairs.
3. The semiconductor circuit according to claim 2 , further comprising:
a decision circuit which sets said priority among said access ports.
4. A semiconductor circuit on a semiconductor chip comprising:
a first access port and a second access port;
a plurality of memory banks which can be accessed through both said first access port and said second access port; and
a decision circuit which sets said priority among said access ports;
wherein each of said plurality of memory banks includes a plurality of word lines, a plurality of bit lines, a plurality of DRAM cells, and a sense amplifier circuit,
wherein one of said first and second access ports has priority over the other of said first and second access ports when said first and second access ports access a same memory bank of said plurality of memory banks, and
wherein said first and second access ports handle different bit widths.
5. The semiconductor circuit according to claim 4 , further comprising:
a hit/miss judgment circuit,
wherein said hit/miss judgment circuit judges hit/miss based on access request, and outputs data which is already latched by said sense amplifier to said global bit lines in case of hit.
6. The semiconductor circuit according to claim 5 ,
wherein an access to one of said plurality of memory banks through said first access port and an access to another one of said plurality of memory banks through said second access port has an overlapping period.
7. A semiconductor circuit on a semiconductor chip comprising:
a first access port and a second access port;
a plurality of memory banks which can be accessed through said first access port and said second access port;
wherein said plurality of memory banks each includes a plurality of word lines, a plurality of bit lines, a plurality of memory DRAM cells, and a sense amplifier circuit,
wherein one of said first and second access ports has priority over the other of said first and second access ports when there is a conflict between accesses from said first access port and said second access port, and
wherein when an access through said first access port is a miss and an access through said second access port is a hit, data is outputted through said second access port until an output through said first access port is ready.
8. The semiconductor circuit according to claim 7 ,
wherein said plurality of memory banks each further includes global bit lines coupled to said plurality of bit pairs.
9. The semiconductor circuit according to claim 8 , further comprising:
a hit/miss judgment circuit,
wherein said first access port and said second access port handle different bit widths, and
wherein said hit/miss judgment circuit judges hit/miss based on access request, and outputs data which is already latched by said sense amplifier to said global bit lines in case of hit.
10. The semiconductor circuit according to claim 9 ,
wherein an access to one of said plurality of memory banks through said first access port and an access to another one of said plurality of memory banks through said second access port has an overlapping period.